Version Not Found

go.etcd.io/etcd v0.5.0-alpha.5.0.20150813172005-ab5a69cb1872

The requested version v0.5.0-alpha.5.0.20150813172005-ab5a69cb1872 cannot be found for package go.etcd.io/etcd. Go to the default version (v0.4.9) instead.