update deprecated syntax

see https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

Author: akeeman

deployments/aws.yml

@@ -75,7 +75,7 @@ jobs:
         # be deployed to ECS.
         docker build -t $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG .
         docker push $ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG
-        echo "::set-output name=image::$ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG"
+        echo "image=$ECR_REGISTRY/$ECR_REPOSITORY:$IMAGE_TAG" >> $GITHUB_OUTPUT
 
     - name: Fill in the new image ID in the Amazon ECS task definition
       id: task-def