Update README version

Previous version I forgot to bump it

Author: Patrick Robinson

README.md

@@ -15,7 +15,7 @@ steps:
     concurrency_group: "my-service-deploy"
     concurrency: 1
     plugins:
-      - ecs-deploy#v1.3.0:
+      - ecs-deploy#v1.4.0:
           cluster: "my-ecs-cluster"
           service: "my-service"
           task-definition: "examples/hello-world.json"