This also incorporates the version string into the package name so
that incompatibile versions will fail to connect.
Arbitrary choices:
- The proto3 package name is runtime.v1alpha2. The proto compiler
normally translates this to a go package of "runtime_v1alpha2", but
I renamed it to "v1alpha2" for consistency with existing packages.
- kubelet/apis/cri is used as "internalapi". I left it alone and put the
public "runtimeapi" in kubelet/apis/cri/runtime.
Module remotecommand originally part of kubernetes/pkg/client/unversioned was moved
to client-go/tools, and will be used as authoritative in kubectl, e2e and other places.
Module remotecommand relies on util/exec module which will be copied to client-go/pkg/util