Update dependabot for composite actions

Author: TonyCTHsu

.github/dependabot.yml

@@ -6,9 +6,11 @@
 version: 2
 updates:
   - package-ecosystem: "github-actions"
-    directory: "/"
+    directories:
+      - "/"
+      - ".github/actions/*"
     schedule:
-      interval: "monthly"
+      interval: "weekly"
     groups:
       gh-actions-packages:
         patterns: