Have Dependabot monitor GitHub Actions

.github/dependabot.yml

@@ -0,0 +1,16 @@
+# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+# https://docs.github.com/code-security/dependabot/dependabot-version-updates/customizing-dependency-updates
+#
+# See: https://www.github.com/dependabot/dependabot-core/issues/4605
+---
+# yaml-language-server: $schema=https://json.schemastore.org/dependabot-2.0.json
+version: 2
+updates:
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+      day: tuesday
+    groups:
+      all-github-actions:
+        patterns: ['*']