Prepare for 7.6.0 Release

[azeey]

🎈 Release

Preparation for 7.6.0 release.

Comparison to 7.5.0: gz-sim7_7.5.0...gz-sim7

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 #2173 (3e7aa0a) into gz-sim7 (5dbbd1b) will increase coverage by 0.02%.
The diff coverage is n/a.

❗ Current head 3e7aa0a differs from pull request most recent head ad6f7e8. Consider uploading reports for the commit ad6f7e8 to get more accurate results

@@             Coverage Diff             @@
##           gz-sim7    #2173      +/-   ##
===========================================
+ Coverage    65.00%   65.02%   +0.02%     
===========================================
  Files          356      356              
  Lines        28932    28932              
===========================================
+ Hits         18808    18814       +6     
+ Misses       10124    10118       -6     

see 1 file with indirect coverage changes

[azeey]

There was an issue with the gz-plugin release causing the Ubuntu CI to fail during installation of dependencies. I had to make another release after merging gazebo-release/gz-plugin2-release#16. It looks fine now, except the flaky test UNIT_Server_TEST, so I'll go ahead and merge.