Check registry aliases when trying cross-repository mounts

[briandealwis]

Pulling from registry-1.docker.io and pushing to registry.hub.docker.com should still be able to use the cross-repository mounts since they're aliases.

[loosebazooka]

How would we know this? Just some table of known aliases?

[briandealwis]

Yeah.

https://github.com/GoogleContainerTools/jib/blob/7e3695b5a3884c6c88f8c146358dc2b577c7c87a/jib-core/src/main/java/com/google/cloud/tools/jib/registry/RegistryAliasGroup.java#L30-L34