Updates to AWS ECS deploy guide (#3002)

Author: thekaveman

content/actions/guides/deploying-to-amazon-elastic-container-service.md

@@ -107,7 +107,7 @@ jobs:
         with:
           aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
           aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
-          aws-region: $AWS_REGION
+          aws-region: ${{ env.AWS_REGION }}
 
       - name: Login to Amazon ECR
         id: login-ecr
@@ -124,22 +124,22 @@ jobs:
           # be deployed to ECS.
           docker build -t $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG .
           docker push $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG
-          echo "image=$ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG" >> $GITHUB_ENV
+          echo "::set-output name=image::$ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG"
 
       - name: Fill in the new image ID in the Amazon ECS task definition
         id: task-def
         uses: aws-actions/amazon-ecs-render-task-definition@v1
         with:
-          task-definition: $ECS_TASK_DEFINITION
-          container-name: $CONTAINER_NAME
+          task-definition: ${{ env.ECS_TASK_DEFINITION }}
+          container-name: ${{ env.CONTAINER_NAME }}
           image: ${{ steps.build-image.outputs.image }}
 
       - name: Deploy Amazon ECS task definition
         uses: aws-actions/amazon-ecs-deploy-task-definition@v1
         with:
           task-definition: ${{ steps.task-def.outputs.task-definition }}
-          service: $ECS_SERVICE
-          cluster: $ECS_CLUSTER
+          service: ${{ env.ECS_SERVICE }}
+          cluster: ${{ env.ECS_CLUSTER }}
           wait-for-service-stability: true
 ```
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