I am trying to create a Nexus clean up policy to prune all unused docker images in my repository except for my "flannel" docker image.
I have created ^((?!flannel).)*$ regex pattern for all strings excluding "flannel" and tested this pattern in regextester.com but unfortunately regex patterns are not working for me, eventhough it is stated here in the docs that Nexus Sonatype supports Reges Patterns.
I am using Nexus Sonatype OSS 3.21.1-01 version.