llvmlite 0.42.0 Checklist

[stuartarchibald]

llvmlite 0.42.0

• Cherry-pick items from the 0.42.0 milestone into a PR targeting the release branch. N/A, no changes required.
• Update CHANGE_LOG on cherry-pick-PR (Update CHANGE_LOG for 0.42.0 final. #1029).
• Have cherry-pick-PR reviewed and merged. none
• Test HEAD of release branch on buildfarm (pre-tag testing):
  • conda package build and test.
  • wheel build.
• Annotated tag v0.42.0 on release branch (llvmlite tags DO have a v prefix).
• Build and upload conda packages on buildfarm (check "upload"). llvmlite_272
• Build wheels and sdist on the buildfarm (check "upload"). llvmlite_wheel_60
• Verify packages uploaded to Anaconda Cloud and copy to numba/label/main.
• Upload wheels and sdist to PyPI. (upload from ci_artifacts).
• Verify wheels for all platforms arrived on PyPi.
• Verify ReadTheDocs build.
• Send RC/FINAL announcement email / post announcement to discourse group.
• Post link to Twitter and Mastodon and anywhere else that is appropriate.

Post release

• Cherry-pick changes to the CHANGE_LOG to main. (FINAL ONLY) v0.42 Post release  #1032
• Clean up ci_artifacts by moving files to subdirectories
• Update release checklist template with any additional bullet points that
  may have arisen during the release.
• Ping Anaconda Distro team to trigger a build for defaults (FINAL ONLY).
• Close milestone (and then close this release issue).