oras-project / oras-go

The MIGRATION_GUIDE.md is outdated and does not reflect oras-go v2.5.0.

For example,

Line 20 in 9b6f321

    
           - No longer supports `docker.Login` and `docker.Logout` (removes the dependency on `docker`); instead, provides authentication through [auth.Client](https://pkg.go.dev/oras.land/oras-go/v2/registry/remote/auth#Client)

does not hold any longer since we have the credentials pacakge.

Update v1 to v2 migration guide