Improve changelogs

[kaylareopelle]

It's difficult for me to trace the exact change related to a given release. I think we can make some updates to the structure of the changelog to make things more user-friendly.

Some improvements ideas:

• Add a link to the PR(s) that caused the change
• Use the PR title as the changelog title
• Include a description for the change (perhaps we can have PR descriptions or content beneath a specific heading determine the description)
• Have an overall release changelog for contrib as a whole (which PRs have been released? what gems did they impact?)
  • Maybe this looks like a tag that's easy to filter on PRs? Maybe something like this exists and I'm now aware?

[github-actions[bot]]

👋 This issue has been marked as stale because it has been open with no activity. You can: comment on the issue or remove the stale label to hold stale off for a while, add the keep label to hold stale off permanently, or do nothing. If you do nothing this issue will be closed eventually by the stale bot.