Update changelog for 8.12.2

[JoshMock]

• Backport changelog for 8.12.1
• Add changelog for 8.12.2

[github-actions]

The backport to 8.12 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-8.12 8.12
# Navigate to the new working tree
cd .worktrees/backport-8.12
# Create a new branch
git switch --create backport-2139-to-8.12
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 1d8da99d5bb9c282e7ecd500620c45024fafccfc
# Push it to GitHub
git push --set-upstream origin backport-2139-to-8.12
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-8.12

Then, create a pull request where the base branch is 8.12 and the compare/head branch is backport-2139-to-8.12.