update readme

Author: sebastian-stephan

README.md

@@ -4,7 +4,7 @@ A github action, that updates a service with a new image based on an existing ta
 
 ## Usage
 ```yaml
-      - name: deploy to Dev
+      - name: deploy to ECS
         uses: modum-io/aws-ecs-deploy-service-by-template
         with:
           image: "modumio/sample@${{ steps.docker_build.outputs.digest }}"