ci(dependabot): update GitHub Action images automatically

.github/dependabot.yml

@@ -13,3 +13,15 @@ updates:
   commit-message:
     prefix: chore
     include: scope
+
+- package-ecosystem: github-actions
+  directory: "/"
+  open-pull-requests-limit: 5
+  schedule:
+    interval: weekly
+  target-branch: master
+  reviewers:
+    - Deuchnord
+  commit-message:
+    prefix: ci
+    include: scope