Bump GitHub Actions across workflows (#16091)

* Bump GitHub Actions across workflows

Update workflow dependencies to newer major versions in repository automation files. This upgrades `actions/checkout` to v7, `actions/github-script` to v9, `actions/create-github-app-token` to v3, and GitHub Pages actions (`upload-pages-artifact` and `deploy-pages`) to v5 to keep CI/CD and maintenance workflows current.

* add dependabot for gh actions

.github/dependabot.yml

@@ -0,0 +1,17 @@
+# Keeps the GitHub Actions referenced in .github/workflows up to date.
+# https://docs.github.com/code-security/dependabot/working-with-dependabot/dependabot-options-reference
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+    open-pull-requests-limit: 5
+    labels:
+      - "dependencies"
+    # One PR per week for all action bumps instead of one PR per action.
+    groups:
+      github-actions:
+        patterns:
+          - "*"