chore: git cache cleanup

.github/workflows/gh_cache_cleanup.yml

@@ -0,0 +1,31 @@
+name: Cleanup github runner caches on closed pull requests
+on:
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: 'PR number to clean caches for'
+        required: true
+        type: string
+
+jobs:
+  cleanup:
+    runs-on: ubuntu-latest
+    permissions:
+      actions: write
+    steps:
+      - name: Cleanup
+        run: |
+          echo "Fetching list of cache keys"
+          cacheKeysForPR=$(gh cache list --ref "$BRANCH" --limit 100 --json id --jq '.[].id')
+
+          ## Setting this to not fail the workflow while deleting cache keys.
+          set +e
+          echo "Deleting caches..."
+            while IFS= read -r cacheKey; do
+              gh cache delete "$cacheKey"
+            done <<< "$cacheKeysForPR"
+          echo "Done"
+        env:
+          GH_TOKEN: ${{ github.token }}
+          GH_REPO: ${{ github.repository }}
+          BRANCH: refs/pull/${{ inputs.pr_number }}/merge