Let's make the release process smoother and less prone to human error in release notes generation by auto generating release notes based on the commits since the last release.

From slack thread: https://mongodb.slack.com/archives/G2L10JAV7/p1652789425871859

Maurizio:
"Github apparently is capable to auto-generate notes out of PRs and filter them based on labels, so I’m thinking something like this:
If a PR [commit] is not a `feat` or `fix`, for example a chore, then is excluded from release notes.
If instead is a `feat` or a `fix`, then it MUST have either a `feature-flagged`, or a `ok-for-release-notes` label. (is really easy to add a check for that so we don’t forget to add it).
So then we can generate release notes and include only PRs that have the `ok-for-release-notes` label."