add dependabot

Author: xopham

.github/dependabot.yml

@@ -0,0 +1,16 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file
+
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directories:
+      - "/.github/workflows"
+    schedule:
+      interval: "monthly"
+    groups:
+      gh-actions-packages:
+        patterns:
+          - "*"