rlua release checklist

Basic README.md check
Update CHANGELOG.md with important changes since last release
For a maintenance release:
- Check if there are any bugfixes on master which should be included
Update version number in Cargo.toml
Check other fields in Cargo.toml are sensible
Check that CI is passing
Tag the commit for the release
Run cargo publish --dry-run -sys crates if updated.
Run cargo publish --dry-run on main crate.
Run cargo publish on -sys crates if updated.
Run cargo publish
Check that the version from crates.io looks good
Update version number on branch to (next version)-alpha.

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