Release v2.3.1

[rehandalal]

Welcome Release Captain! ⛵️

• Assign this issue to yourself.
• Set up your workspace as described in the docs.
• Checkout and update the main branch locally.
• Start a new branch. If you know the version you'll be releasing, name it release-NEW_VERSION. If you don't, you can rename it later when you do know.
• Update CHANGELOG.md to reflect the changes since the last version.
  • Use the command git log --merges vOLD_VERSION.. to see commits between then and now.
• git add CHANGELOG.md, since the next step will commit it.
• Use yarn to bump the version. Use one of the following, depending on the version difference:
  • yarn version --patch - Bug fixes, doc updates, and other small changes.
  • yarn version --minor - New features and backwards compatible pages.
  • yarn version --major - Breaking changes and major new features.
• If necessary, rename your branch with git branch -m release-NEW_VERSION.
• Rename this issue with the version number as Release vNEW_VERSION
• Make a PR to merge this branch. Add Refs #XYZ to the body where XYZ is this issue.
• Get the change reviewed and merged.
• git push --tags
• Create a new extension release with Shipit based on the tagged commit (not the merged commit).
• Get that shipit extension approved, and get a final signed XP built.
• Rename the XPI file to normandy-devtools@mozilla.com-NEW_VERSION-signed.xpi.
• Update the Github release for the newly pushed tag with the contents from CHANGELOG.md and attach the signed XPI.
• Make any needed changes to the release issue template, get them reviewed and merged.
• Create a release issue for with the release issue template.
• Close this issue.

[rehandalal]

Skipped branch rename since PR had already been r+'ed