ci: Try default GitHub token

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

.github/workflows/dependabot-approve-merge.yml

@@ -49,4 +49,3 @@ jobs:
         with:
           target: 'minor'
           use-github-auto-merge: true
-          github-token: ${{ secrets.DEPENDABOT_AUTOMERGE_TOKEN }}