Add auto-merge & approve

Author: wei18

.github/workflows/Dependabot.yml

@@ -39,6 +39,6 @@ jobs:
           git config user.email "${GITHUB_ACTOR}@users.noreply.github.com"
           make install
           git push
-          # gh pr review --approve "$PR_URL"
-          # gh pr merge --auto --merge "$PR_URL"
+          gh pr merge --auto --merge "$PR_URL"
+          gh pr review --approve "$PR_URL"