Updates docker login action to v2

to fix warning `save-state command is deprecated
and will be disabled soon`

.github/workflows/build-citus-community-nightlies.yml

@@ -42,7 +42,7 @@ jobs:
 
       # This step is to fetch the images unanonymously to have higher bandwidth
       - name: Login to Docker Hub
-        uses: docker/login-action@v1
+        uses: docker/login-action@v2
         with:
           username: ${{ secrets.DOCKERHUB_USER_NAME }}
           password: ${{ secrets.DOCKERHUB_PASSWORD }}