Prepare for 12.2.2 Release

[azeey]

🎈 Release

Preparation for 12.2.2 release. This will be the final release of gz-transport as it has reached EOL with Garden

Part of gazebo-tooling/release-tools#1165

Comparison to 12.2.1: gz-transport12_12.2.1...gz-transport12

Checklist

• Asked team if this is a good time for a release
• There are no changes to be ported from the previous major version
• No PRs targeted at this major version are close to getting in
• Bumped minor for new features, patch for bug fixes
• Updated changelog
• Updated migration guide (as needed)
• Link to PR updating dependency versions in appropriate repository in gazebo-release (as needed):

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.31%. Comparing base (ca954cb) to head (46ceda2).
Report is 5 commits behind head on gz-transport12.

Additional details and impacted files

@@                Coverage Diff                 @@
##           gz-transport12     #553      +/-   ##
==================================================
+ Coverage           87.23%   87.31%   +0.07%     
==================================================
  Files                  60       60              
  Lines                5211     5211              
==================================================
+ Hits                 4546     4550       +4     
+ Misses                665      661       -4     

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[azeey]

The gz-transport failure on homebrew is a known failure #509, so I'll go ahead and merge this.