Prepare for 7.2.1 Release

[azeey]

🎈 Release

Preparation for 7.2.1 release.

Comparison to 7.2.0: gz-gui7_7.2.0...gz-gui7

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

Merging #576 (346e581) into gz-gui7 (c020e25) will not change coverage.
The diff coverage is n/a.

❗ Current head 346e581 differs from pull request most recent head e7e87a9. Consider uploading reports for the commit e7e87a9 to get more accurate results

@@           Coverage Diff            @@
##           gz-gui7     #576   +/-   ##
========================================
  Coverage    70.91%   70.91%           
========================================
  Files           45       45           
  Lines         4941     4941           
========================================
  Hits          3504     3504           
  Misses        1437     1437