Version Not Found

go.etcd.io/etcd v0.5.0-alpha.5.0.20170616193708-e475a4ea7104

The requested version v0.5.0-alpha.5.0.20170616193708-e475a4ea7104 cannot be found for package go.etcd.io/etcd. Go to the default version (v0.4.9) instead.