Update cicd.yaml

only login when using master

.github/workflows/cicd.yaml

@@ -21,15 +21,16 @@ jobs:
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v2
 
+    - name: Build Docker image
+      run: docker build -t server .
+
     - name: Log in to Docker Hub
       uses: docker/login-action@v2
+      if: github.ref == 'refs/heads/master'
       with:
         username: ${{ secrets.DOCKER_USERNAME }}
         password: ${{ secrets.DOCKER_PASSWORD }}
 
-    - name: Build Docker image
-      run: docker build -t server .
-
     - name: Push Docker image
       if: github.ref == 'refs/heads/master'
       run: docker push server:latest