github: create dependabot.yml [skip ci]

.github/dependabot.yml

@@ -0,0 +1,9 @@
+---
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+    commit-message:
+      prefix: "github: [skip ci]"