Add Dependabot configuration for GitHub Actions

.github/dependabot.yml

@@ -0,0 +1,13 @@
+# Set update schedule for GitHub Actions
+# From: https://docs.github.com/en/code-security/dependabot/working-with-dependabot/keeping-your-actions-up-to-date-with-dependabot
+
+# Enable dependency graph:
+version: 2
+updates:
+
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      # Check for updates to GitHub Actions every month, valid values:
+      # https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#scheduleinterval
+      interval: "monthly"