Update maintainers (backport #362)

[mergify]

This is an automatic backport of pull request #362 done by Mergify.
Cherry-pick of 9bcc813 has failed:

On branch mergify/bp/galactic/pr-362
Your branch is up to date with 'origin/galactic'.

You are currently cherry-picking commit 9bcc813.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   ament_cmake/package.xml
	both modified:   ament_cmake_auto/package.xml
	both modified:   ament_cmake_core/package.xml
	both modified:   ament_cmake_export_definitions/package.xml
	both modified:   ament_cmake_export_dependencies/package.xml
	both modified:   ament_cmake_export_include_directories/package.xml
	both modified:   ament_cmake_export_interfaces/package.xml
	both modified:   ament_cmake_export_libraries/package.xml
	both modified:   ament_cmake_export_link_flags/package.xml
	both modified:   ament_cmake_export_targets/package.xml
	deleted by us:   ament_cmake_gen_version_h/package.xml
	both modified:   ament_cmake_gmock/package.xml
	both modified:   ament_cmake_google_benchmark/package.xml
	both modified:   ament_cmake_gtest/package.xml
	both modified:   ament_cmake_include_directories/package.xml
	both modified:   ament_cmake_libraries/package.xml
	both modified:   ament_cmake_nose/package.xml
	both modified:   ament_cmake_pytest/package.xml
	both modified:   ament_cmake_python/package.xml
	both modified:   ament_cmake_target_dependencies/package.xml
	both modified:   ament_cmake_test/package.xml
	both modified:   ament_cmake_version/package.xml

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/github/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

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