ci: use github app instead of token

[inimaz]

Would it be possible to use a github app instead of passing a github token ?
Not sure it applies here, but Sebastian Ramirez gave a great feedback about his use of it there : https://bsky.app/profile/tiangolo.com/post/3msy3sbkgxc23

Originally posted by @SaboniAmine in #1393 (comment)

Acceptance criteria

All github action flows doing {{secrets.GITHUB_TOKEN}} use the Github app as authentication instead.