Update Makefile

Makefile

@@ -11,7 +11,7 @@ image:
 	docker tag $(PREFIX)/$(REPO_NAME) $(PREFIX)/$(REPO_NAME):$(TAG)  # Add the version tag to the latest image
 
 push: image
-	docker login -u $DOCKER_USER -p $DOCKER_PASS
+	echo "$DOCKER_PASSWORD" | docker login -u "$DOCKER_USERNAME" --password-stdin
 	docker push $(PREFIX)/$(REPO_NAME) # Push image tagged as latest to repository
 	docker push $(PREFIX)/$(REPO_NAME):$(TAG) # Push version tagged image to repository (since this image is already pushed it will simply create or update version tag)