Update path of GPL includes (backport #1994)

[mergify]

Needs release 0.4.0
for reference, see PickNikRobotics/generate_parameter_library#213

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This is an automatic backport of pull request #1994 done by Mergify.

[mergify]

Cherry-pick of f8c03cc has failed:

On branch mergify/bp/humble/pr-1994
Your branch is up to date with 'origin/humble'.

You are currently cherry-picking commit f8c03cc.
  (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 <file>..." to mark resolution)
	both modified:   controller_manager/src/controller_manager.cpp

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/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[christophfroehlich]

not needed, we don't use GPL on humble