Merge #1170

1170: build(deps): bump sigma_fun from `9e5e193` to `b511ab5` r=delta1 a=dependabot[bot]

Bumps [sigma_fun](https://github.com/LLFourn/secp256kfun) from `9e5e193` to `b511ab5`.
<details>
<summary>Commits</summary>
<ul>
<li><a href="b511ab5f83"><code>b511ab5</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/LLFourn/secp256kfun/issues/127">#127</a> from LLFourn/poly</li>
<li><a href="830773e6c1"><code>830773e</code></a> Merge pull request <a href="https://github-redirect.dependabot.com/LLFourn/secp256kfun/issues/129">#129</a> from LLFourn/derive_nonce_rng_fixed_length</li>
<li><a href="f145d900fe"><code>f145d90</code></a> Remove .borrow from derive_nonce_rng</li>
<li><a href="91e9a58d26"><code>91e9a58</code></a> [frost] Documentation improvements</li>
<li><a href="bf68577be4"><code>bf68577</code></a> [frost] Fix revert to G on zero agg nonce mechanism</li>
<li><a href="16255bb0bc"><code>16255bb</code></a> Allow HashInto for Zero points</li>
<li><a href="3971cedb06"><code>3971ced</code></a> [frost] Move proptest into /tests</li>
<li><a href="70c77e06b4"><code>70c77e0</code></a> [frost] Add simulate_keygen</li>
<li><a href="c03eaf1c76"><code>c03eaf1</code></a> Remove *Poly types</li>
<li><a href="bf3bb56c07"><code>bf3bb56</code></a> Relax type contraints for *::zero *::one</li>
<li>Additional commits viewable in <a href="9e5e193347...b511ab5f83">compare view</a></li>
</ul>
</details>
<br />


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Cargo.lock

@@ -980,7 +980,7 @@ checksum = "5caaa75cbd2b960ff1e5392d2cfb1f44717fffe12fc1f32b7b5d1267f99732a6"
 [[package]]
 name = "ecdsa_fun"
 version = "0.7.1"
-source = "git+https://github.com/LLFourn/secp256kfun#9e5e193347bcffc086d35fa5d8a5a1d5081adf64"
+source = "git+https://github.com/LLFourn/secp256kfun#b511ab5f83aa0ae21f10460ada56f535ad3a6d57"
 dependencies = [
  "bincode",
  "rand_chacha 0.3.1",
@@ -3428,7 +3428,7 @@ dependencies = [
 [[package]]
 name = "secp256kfun"
 version = "0.7.1"
-source = "git+https://github.com/LLFourn/secp256kfun#9e5e193347bcffc086d35fa5d8a5a1d5081adf64"
+source = "git+https://github.com/LLFourn/secp256kfun#b511ab5f83aa0ae21f10460ada56f535ad3a6d57"
 dependencies = [
  "digest 0.10.5",
  "rand_core 0.6.2",
@@ -3625,7 +3625,7 @@ dependencies = [
 [[package]]
 name = "sigma_fun"
 version = "0.4.1"
-source = "git+https://github.com/LLFourn/secp256kfun#9e5e193347bcffc086d35fa5d8a5a1d5081adf64"
+source = "git+https://github.com/LLFourn/secp256kfun#b511ab5f83aa0ae21f10460ada56f535ad3a6d57"
 dependencies = [
  "curve25519-dalek-ng",
  "digest 0.10.5",