Fix changelog automation

[adamziel]

The changelog-generating job wasn't running lately. This PR connects it to Release NPM packages workflow success and fixes a few subtle bugs.

Testing instructions

• Run npm run changelog locally and confirm it worked
• That's about it :( We'll need to wait until the next package release to confirm it worked.

[brandonpayton]

Unfortunately, it looks like the changelog update workflow failed this morning:
https://github.com/WordPress/wordpress-playground/actions/runs/9177933181/job/25236668463#step:6:18

This appears to be because the workflow does not commit the changes to packages/docs/site/docs/17-changelog.md.

% bun packages/docs/site/bin/refresh-changelog.ts Changelog copied and frontmatter prepended successfully! % git status ... Changes not staged for commit: (use "git add <file>..." to update what will be committed) (use "git restore <file>..." to discard changes in working directory) modified: CHANGELOG.md modified: packages/docs/site/docs/17-changelog.md 

We only commit one of the changed files:

if [[ -n $(git status --porcelain CHANGELOG.md) ]]; then git commit CHANGELOG.md -m "chore: update changelog" git pull origin trunk --rebase git push origin trunk else 

which leads to the error:

[trunk 33278bf] chore: update changelog 1 file changed, 1 insertion(+), 82 deletions(-) error: cannot pull with rebase: You have unstaged changes. error: Please commit or stash them. Error: Process completed with exit code 128. 

[brandonpayton]

Working on a fix for this.

[brandonpayton]

PR here: #1449