(docs): Docker image does not exist in documented repository - reopen #206

[malte-aws]

link to reference doc page

https://github.com/aws-cloudformation/aws-guard-rules-registry/blob/main/docs/Using-Guard-Rules-Registry.md

Describe your issue?

Reopen #206

The documentation states that the image is available at docker pull public.ecr.aws/r7q6h7y6/guard:1.0.1.

But the guard repository does not exist in that registry. The pull command results in the following error:
Error response from daemon: repository public.ecr.aws/r7q6h7y6/guard not found: name unknown: The repository with name 'guard' does not exist in the registry with id 'r7q6h7y6'.