Rules migrated to github.com/google/go-containerregistry

container_pull, container_layer, container_image, container_flatten and container_push now use Go binaries based on github.com/google/go-containerregistry instead of github.com/google/containerregistry.

Fixes

• Final fixes for mac using toolchains properly in py_binary target with bazel head (#1191)
• fixing rules_docker with bazel head (#1190)
• Remove references to python binaries using python containerregistry (#1189)
• Update README.md (#1188)
• Deprecate python puller, loader & pusher. (#1186)