This also formats `log` events more nicely. Instead of
```
Mar 29 09:46:16.775 INFO log: Found message after comparing 82 lines log.target="testcontainers::core::wait_for_message" log.module_path="testcontainers::core::wait_for_message" log.file="/home/thomas/.cargo/registry/src/github.com-1ecc6299db9ec823/testcontainers-0.12.0/src/core/wait_for_message.rs" log.line=35
```
We now have
```
Mar 29 09:57:15.860 INFO testcontainers::core::wait_for_message: Found message after comparing 81 lines
```
Upgrade bitcoin harness dependency to latest commit
Upgrade backoff to fix failing tests. The previous version of backoff had a broken version of the retry function. Upgraded to a newer comit which fixes this problem.
Upgrade hyper to 0.14 as the 0.13 was bringing in tokio 0.2.24
Upgraded bitcoin harness to version that uses tokio 1.0 and reqwest 0.11
Upgrade reqwest to 0.11. Reqwest 0.11 uses tokio 1.0
Upgrade libp2p to 0.34 in preparation for tokio 1.0 upgrade
