ci: add scheduled action to clear github caches

Author: brianheineman

.github/workflows/clear-caches.yml

@@ -0,0 +1,19 @@
+# Clearing caches regularly takes care of caches growing to problematic size over time
+
+name: Clear caches
+
+on:
+  schedule:
+    - cron: '0 4 * * MON'
+  workflow_dispatch:
+
+jobs:
+  clear-caches:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Clear all caches
+        run: gh cache delete --all
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}