Prepare for 4.1.0 Release

[scpeters]

🎈 Release

Preparation for 4.1.0 release.

Comparison to 4.0.0: https://github.com/gazebosim/gz-cmake/compare/gz-cmake4_4.0.0...gz-cmake4

Needed by https://github.com/gazebosim/gz-math/pull/639

Checklist

• [x] Asked team if this is a good time for a release
• [x] There are no changes to be ported from the previous major version
• [x] No PRs targeted at this major version are close to getting in
• [x] Bumped minor for new features, patch for bug fixes
• [x] 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.

[scpeters]

fixing "add ticket to inbox" in #459