Minor changes to the release workflow

[llewelld]

✅ Checklist

• You have given your pull request a meaningful title (e.g. Enable foobar integration rather than 515 foobar).
• You are targeting the appropriate branch. If you're not certain which one this is, it should be develop.
• Your branch is up-to-date with the target branch (it probably was when you started, but it may have changed since then).

🚦 Depends on

No dependencies.

⤴️ Summary

The Contributing file has details aimed at helping maintainers with the release workflow. There process has changed since the instructions were written with additional workflows to support the release process. Some minor errors in the commands have also been fixed to avoid tripping up potential contirbutors.

🌂 Related issues

There's no issue associated with this as it's just minor changes to the CONTRIBUTORS.md file.

🔬 Tests

I've not performed any tests, other than the recent release process, which is what exposed the need for these updates to the documentation.

It's all minor stuff, but things that could trip up a contributor following the steps to the letter.

[github-actions]

Coverage report

This PR does not seem to contain any modification to coverable code.