Merge #357

357: Bump tokio from 1.3.0 to 1.4.0 r=thomaseizinger a=dependabot[bot]

Bumps [tokio](https://github.com/tokio-rs/tokio) from 1.3.0 to 1.4.0.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/tokio-rs/tokio/releases">tokio's releases</a>.</em></p>
<blockquote>
<h2>Tokio v1.4.0</h2>
<h3>Added</h3>
<ul>
<li>macros: introduce biased argument for <code>select!</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3603">#3603</a>)</li>
<li>runtime: add <code>Handle::block_on</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3569">#3569</a>)</li>
</ul>
<h3>Fixed</h3>
<ul>
<li>runtime: avoid unnecessary polling of <code>block_on</code> future (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3582">#3582</a>)</li>
<li>runtime: fix memory leak/growth when creating many runtimes (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3564">#3564</a>)</li>
<li>runtime: mark <code>EnterGuard</code> with <code>must_use</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3609">#3609</a>)</li>
</ul>
<h3>Documented</h3>
<ul>
<li>chore: mention fix for building docs in contributing guide (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3618">#3618</a>)</li>
<li>doc: add link to <code>PollSender</code> (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3613">#3613</a>)</li>
<li>doc: alias sleep to delay (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3604">#3604</a>)</li>
<li>sync: improve <code>Mutex</code> FIFO explanation (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3615">#3615</a>)</li>
<li>timer: fix double newline in module docs (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3617">#3617</a>)</li>
</ul>
<p><a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3564">#3564</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3564">tokio-rs/tokio#3564</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3613">#3613</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3613">tokio-rs/tokio#3613</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3618">#3618</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3618">tokio-rs/tokio#3618</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3617">#3617</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3617">tokio-rs/tokio#3617</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3582">#3582</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3582">tokio-rs/tokio#3582</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3615">#3615</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3615">tokio-rs/tokio#3615</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3603">#3603</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3603">tokio-rs/tokio#3603</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3609">#3609</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3609">tokio-rs/tokio#3609</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3604">#3604</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3604">tokio-rs/tokio#3604</a>
<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3569">#3569</a>: <a href="https://github-redirect.dependabot.com/tokio-rs/tokio/pull/3569">tokio-rs/tokio#3569</a></p>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="dcac336dc7"><code>dcac336</code></a> chore: prepare Tokio v1.4.0 (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3621">#3621</a>)</li>
<li><a href="c39d9867bb"><code>c39d986</code></a> runtime: add Handle::block_on (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3569">#3569</a>)</li>
<li><a href="e4f76688a0"><code>e4f7668</code></a> runtime: fix memory leak/growth when creating many runtimes (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3564">#3564</a>)</li>
<li><a href="e6103d6661"><code>e6103d6</code></a> docs: add link to PollSender (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3613">#3613</a>)</li>
<li><a href="cc90a5c679"><code>cc90a5c</code></a> chore: mention fix for building docs in contributing guide (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3618">#3618</a>)</li>
<li><a href="f107c4f49b"><code>f107c4f</code></a> timer: fix double newline in module docs (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3617">#3617</a>)</li>
<li><a href="e6a9167bb7"><code>e6a9167</code></a> runtime: avoid unnecessary polling of block_on future (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3582">#3582</a>)</li>
<li><a href="345b29ca11"><code>345b29c</code></a> sync: improve Mutex FIFO explanation (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3615">#3615</a>)</li>
<li><a href="b75d02a2b6"><code>b75d02a</code></a> macros: introduce biased argument for select! (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3603">#3603</a>)</li>
<li><a href="a1b4bdee61"><code>a1b4bde</code></a> runtime: mark EnterGuard with must_use (<a href="https://github-redirect.dependabot.com/tokio-rs/tokio/issues/3609">#3609</a>)</li>
<li>Additional commits viewable in <a href="https://github.com/tokio-rs/tokio/compare/tokio-1.3.0...tokio-1.4.0">compare view</a></li>
</ul>
</details>
<br />


[![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=tokio&package-manager=cargo&previous-version=1.3.0&new-version=1.4.0)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores)

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot squash and merge` will squash and merge this PR after your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge and block automerging
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot close` will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
- `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)


</details>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Cargo.lock

@@ -3693,9 +3693,9 @@ checksum = "cda74da7e1a664f795bb1f8a87ec406fb89a02522cf6e50620d016add6dbbf5c"
 
 [[package]]
 name = "tokio"
-version = "1.3.0"
+version = "1.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8d56477f6ed99e10225f38f9f75f872f29b8b8bd8c0b946f63345bb144e9eeda"
+checksum = "134af885d758d645f0f0505c9a8b3f9bf8a348fd822e112ab5248138348f1722"
 dependencies = [
  "autocfg 1.0.1",
  "bytes",