chore: configure Dependabot to group React updates

This ensures react and react-dom are updated together in a single PR,
preventing version mismatch failures in CI.

Author: yogeshchoudhary147

.github/dependabot.yml

@@ -11,3 +11,8 @@ updates:
     ignore:
       - dependency-name: "*"
         update-types: ["version-update:semver-major"]
+    groups:
+      react:
+        patterns:
+          - "react"
+          - "react-dom"