GH: Allow backport workflow to trigger actions

[tvdeyen]

We need this otherwise the created pull request from the backport tool will not trigger any actions (like linting) to run.

[github-actions]

💔 All backports failed

Status	Branch	Result
❌	v4.5	An unhandled error occurred. Please see the logs for details

Manual backport

To create the backport manually run:

backport --pr 6164

Questions ?

Please refer to the Backport tool documentation and see the Github Action logs for details

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.81%. Comparing base (fcf5ade) to head (78e68e7).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6164      +/-   ##
==========================================
+ Coverage   88.47%   88.81%   +0.33%     
==========================================
  Files         764      835      +71     
  Lines       16340    18153    +1813     
==========================================
+ Hits        14457    16122    +1665     
- Misses       1883     2031     +148     

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[tvdeyen]

💚 All backports created successfully

Status	Branch	Result
✅	v4.5

Questions ?

Please refer to the Backport tool documentation

[tvdeyen]

Copy my comment from #6179

This does not help. It only triggers the workflow when a user with workflow permissions create the PR (me in this case). But it does not work if another action creates a PR with the default GITHUB_TOKEN github creates.