use towncrier to handle changelog entries

[zacharyburnett]

using towncrier to handle changelog entries will

• drastically reduce (or even eliminate) branch conflicts in CHANGES.rst we currently experience with PRs
• keep the sections in CHANGES.rst consistent and eliminate duplicate sections
• allow automatic links to be generated in the changelog entries

towncrier expects "news fragment" files (text files in the changes/ directory with filenames in the format <PR#>.<changetype>.rst, i.e. for this PR it would be changes/284.general.rst). See docs at https://towncrier.readthedocs.io/en/latest/tutorial.html#creating-news-fragments

when ready to make a release, run towncrier build to ingest the news fragments and generate a changelog section in CHANGES.rst with all the new change log entries for that release (this clears the changes/ directory of all news fragment files). This step should either be done before making a release, or could probably be added to a GitHub workflow triggered on release (to insert a commit and remake the tag).

After merging this PR the Release Process wiki page will need to be updated to include a step to run towncrier build instead of manually editing CHANGES.rst

Checklist

• added entry in CHANGES.rst (either in Bug Fixes or Changes to API)
• updated relevant tests
• updated relevant documentation
• updated relevant milestone(s)
• added relevant label(s)

[zacharyburnett]

current running change log in docs:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.38%. Comparing base (e3eac20) to head (f637123).
Report is 171 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #284      +/-   ##
==========================================
- Coverage   84.43%   84.38%   -0.06%     
==========================================
  Files          41       41              
  Lines        7583     7557      -26     
==========================================
- Hits         6403     6377      -26     
  Misses       1180     1180              

☔ View full report in Codecov by Sentry.
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[zacharyburnett]

Checklist

• for a public change, added a towncrier news fragment in changes/:

  echo "changed something" > changes/<PR#>.<changetype>.rst

  • changes/<PR#>.apichange.rst: change to public API
  • changes/<PR#>.bugfix.rst: fixes an issue
  • changes/<PR#>.general.rst: infrastructure or miscellaneous change

• updated relevant tests

• updated relevant documentation

• updated relevant milestone(s)

[braingram]

LGTM!