feat: support changelog-individual-file entries for -dev version changes

[ryannikolaidis]

Is your feature request related to a problem? Please describe.
Now that we have added merge queues, the CHANGELOG will be automerged as PRs move through the queue. This will likely lead to conflicts.

Describe the solution you'd like
We should to move to a different scheme where CHANGELOG items accumulate as individual files in a directory rather than in a single file. A supporting release script should be written to accumulate all the -dev changelog-individual-file entries into the main CHANGELOG. This also implies updating our changelog validation in CI (which will now require some custom script to validate a new file was added rather than entry in CHANGELOG.md)

Describe alternatives you've considered
We could potentially have a single -dev changelog file with only changes since the last release. This is probably quite a bit less prone to conflicts than current flow and means you can see all latest changes in a single place.

Additional context

[MthwRobinson]

@ryannikolaidis @ahmetmeleq - Was this implemented in #300?

[ryannikolaidis]

@ryannikolaidis @ahmetmeleq - Was this implemented in #300?

No, this would involve a change to how we currently add per-commit (to main) entries in the changelog. Instead this suggests we have individual changelog files per commit that all get rolled up on release. Advantage here would be that we wouldn't ever hit collisions in the merge queue solely because of changelog conflicts (which will occur on most commits)

[MthwRobinson]

Got it makes sense, we'll keep this open. @ahmetmeleq left a similar comment on one of the PRs yesterday. This looks like a good one to implement and we'll keep it open.

[ahmetmeleq]

@MthwRobinson @ryannikolaidis , it's this one - I'll take another cycle at it when I got time 💪

[ryannikolaidis]

thanks! yea, I suspect this is far lower priority these days, but does make for less changelog management in the long run.