Prepare for 8.1.0 release

[mjcarroll]

🎈 Release

Preparation for 8.1.0 release.

Comparison to 8.0.2: gz-fuel-tools8_8.0.2...gz-fuel-tools8

Needed by <PR(s)>

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 #368 (9ed708f) into gz-fuel-tools8 (5fbf9ef) will not change coverage.
The diff coverage is n/a.

❗ Current head 9ed708f differs from pull request most recent head bed5fcc. Consider uploading reports for the commit bed5fcc to get more accurate results

@@               Coverage Diff               @@
##           gz-fuel-tools8     #368   +/-   ##
===============================================
  Coverage           75.32%   75.32%           
===============================================
  Files                  20       20           
  Lines                2910     2910           
===============================================
  Hits                 2192     2192           
  Misses                718      718