Merge pull request mysql#6 from planetscale/piki/ecr-command

Add more instructions for the ECR command

Author: piki

_planetscale/docs/registry.md

@@ -5,8 +5,13 @@
 
 ### List images
 
-To retrieve details of an image built against a branch:
+To list MySQL container images:
 
 ```
-aws ecr describe-images --profile build-ops --repository-name 'branch/mysql-server' --image-ids imageTag=8.0-latest | jq -r '.imageDetails[]'
+aws --region us-east-1 ecr list-images --profile build --repository-name 'branch/mysql-server' | jq '.imageIds[].imageTag | select(.)'
+```
+
+If necessary, log into the [`build` profile](https://github.com/planetscale/infra/blob/12ae46f94b7b9ad15b0b1ef00c94d544e590c42f/aws_config#L57-L61) first:
+```
+aws sso login --profile build
 ```