OCI Artifact Manifest no longer exists in https://github.com/opencontainers/image-spec/tree/v1.1.0-rc4, oras CLI should remove the v1.1-artifact as an option of --image-spec.

For oras push:

• Remove v1.0-image and v1.1-artifact
• Add new options
  • v1.0: build manifest compliant to image spec v1.0, which doesn't allow --config and --artifact-type to be used at the same time
  • v1.1: build manifest compliant to image spec v1.1.0-rc4

For oras attach:

• Remove --image-spec: oras attach only generate manifests with both subject and artifactType presented