ci: Update workflows

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

.github/workflows/update-nextcloud-ocp-approve-merge.yml

@@ -33,6 +33,12 @@ jobs:
       contents: write
 
     steps:
+      - name: Disabled on forks
+        if: ${{ github.event.pull_request.head.repo.full_name != github.repository }}
+        run: |
+          echo 'Can not approve PRs from forks'
+          exit 1
+
       - uses: mdecoleman/pr-branch-name@bab4c71506bcd299fb350af63bb8e53f2940a599 # v2.0.0
         id: branchname
         with: