ci: add github actions dependency bot config

Author: KazuCocoa

.github/dependabot.yml

@@ -3,6 +3,12 @@ updates:
 - package-ecosystem: bundler
   directory: "/"
   schedule:
-    interval: daily
+    interval: weekly
+    time: "11:00"
+  open-pull-requests-limit: 10
+- package-ecosystem: github-actions
+  directory: "/"
+  schedule:
+    interval: weekly
     time: "11:00"
   open-pull-requests-limit: 10