Version Not Found

go.etcd.io/etcd v0.5.0-alpha.5.0.20150617050017-c4a5088bbc97

The requested version v0.5.0-alpha.5.0.20150617050017-c4a5088bbc97 cannot be found for package go.etcd.io/etcd. Go to the default version (v0.4.9) instead.