.github: purge workflows on deleted branches

No need to keep workflows on already deleted branches, so purge them.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

.github/workflows/tidy-up-auto.yml

@@ -2,6 +2,9 @@ name: delete old workflow runs
 on:
     schedule:
         - cron: '0 0 * * *' # nightly
+    push:
+        branches:
+            - master
 
 jobs:
     delete_old_workflow_runs:
@@ -17,3 +20,16 @@ jobs:
                 repository: ${{ github.repository }}
                 retain_days: 14
                 keep_minimum_runs: 2
+
+    purge_deleted_branch_workflows:
+        runs-on: ubuntu-latest
+        permissions:
+            actions: write
+            contents: read
+        steps:
+            - name: Check out repository code
+              uses: actions/checkout@v4
+            - name: purge workflows on deleted branches
+              run: .github/scripts/github/gh-purge-deleted-branch-workflows.sh X11Libre/xserver
+              env:
+                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}