The `log` crate decided to break support for rustc 1.48 (Debian
bullseye) the day the next release of Debian comes out, obviously
before anyone has had a chance to upgrade to the new Debian
bookworm (at https://github.com/rust-lang/log/pull/543). Thus, we
have to manually pin it back to the previous release.
Sadly, the `log` crate is a transitive dependency of `tokio` until
0.20, which requires rustc 1.49. Luckily at least we won't have to
deal with this again, as `log` won't be a dependency of ours
anymore soon.
To match the local signatures found in test vectors, we must make sure
we don't use any additional randomess when generating signatures, as
we'll arrive at a different signature otherwise.
