Prepare 3.1 release.

Add `.yml` to list of recognised file extensions.

Bump versions to gamma.

Upgrade to macOS 14.

Update crates.

Update to windows-2022 because windows-2019 has been retired.

actions/runner-images#12045

Do not compress with UPX because of "bad DT_GNU_HASH" error.

Bump versions.

Bump version to 2.1.

Clippy.