👷 Drop pull_request_target from commit checker

The job only reads commit messages, which works with the pull_request
trigger for PRs from forks too. Running it on both triggers checked every
PR twice, once with a privileged token it does not need.

Signed-off-by: David Barragán Merino <david.barragan@kaleidos.net>
This commit is contained in:
Internal Server Error - Gitea: Git with a cup of tea
500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f