Refactor versioning process

[sahariko]

Create a new release process for this repository - instead of automatically releasing a new patch version on each commit to master, we'll now run a script that'll handle this process:

1. Generate a changelog section of all new changes since the last version released.
2. Determine what version bump we need to make (minor, patch, etc.).
3. Bump the version in package.json.
4. Update CHANGELOG.md with the new version information.
5. Commit and push changes.
6. Run npm publish only if package.json's version is different than the latest published one.

This release script relies on certain labels being assigned to PRs, which is checked in a different workflow (ensure-pr-labels):

1. Ensure one of the labels we support is present on the PR.

• If there aren't, post a comment on the PR explaining that one of these labels need to be applied and fail CI.
• If there are, delete the previous comment (if it exists, of course).

The comment looks like this: