[WIP] Lotus Release v1.27.0

[rjan90]

🚢 Estimated shipping date

✅ Release Checklist

• Fork a new branch (release/vX.Y.Z) from master and make any further release related changes to this branch. If any "non-trivial" changes get added to the release, uncheck all the checkboxes and return to this stage.
• Bump the version in build/version.go in the master branch to vX.Y.(Z+1)-dev (bump from feature release) or vX.(Y+1).0-dev (bump from mandatory release). Run make gen and make docsgen-cli before committing changes

Prepping an RC:

• version string in build/version.go needs to be updated to end with '-rcX' (in the release/vX.Y.Z branch)
• run make gen && make docsgen-cli
• Generate changelog using the script at scripts/mkreleaselog
• Add contents of generated text to lotus/CHANGELOG.md in addition to other details
• Commit using PR
• tag commit with vX.Y.Z-rcN
• cut a pre-release here

Stable Release

• Final preparation
  • Verify that version string in version.go has been updated.
  • Verify that codegen is up to date (make gen && make docsgen-cli)
  • Ensure that CHANGELOG.md is up to date
  • Merge release-vX.Y.Z into the releases branch.
  • Tag this merge commit (on the releases branch) with vX.Y.Z
  • Cut the release here.

Post-Release

• Merge the releases branch back into master, ignoring the changes to version.go (keep the -dev version from master). Do NOT delete the releases branch when doing so!
• Update RELEASE_ISSUE_TEMPLATE.md with any improvements determined from this latest release iteration.
• Create an issue using RELEASE_ISSUE_TEMPLATE.md for the next release.