Checkout code from pull request head for spotless (#3422) (#3424)

* Checkout code from pull request head for spotless

Signed-off-by: rithin-pullela-aws <rithinp@amazon.com>

* Add name to the ML-Commons checkout

Signed-off-by: rithin-pullela-aws <rithinp@amazon.com>

---------

Signed-off-by: rithin-pullela-aws <rithinp@amazon.com>
(cherry picked from commit 06a2b40)

Co-authored-by: Rithin Pullela <rithinp@amazon.com>

Author: opensearch-trigger-bot[bot]

.github/workflows/CI-workflow.yml

@@ -26,7 +26,10 @@ jobs:
     if: github.repository == 'opensearch-project/ml-commons'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - name: Checkout MLCommons
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
       # Spotless requires JDK 17+
       - name: Setup Java 21
         uses: actions/setup-java@v1