Merge pull request #5384 from mitake/genproto

scripts: pass -u to go get in genproto.sh

scripts/genproto.sh

@@ -38,8 +38,8 @@ ln -s "${PWD}" "${ETCD_ROOT}"
 
 # Ensure we have the right version of protoc-gen-gogo by building it every time.
 # TODO(jonboulle): vendor this instead of `go get`ting it.
-go get github.com/gogo/protobuf/{proto,protoc-gen-gogo,gogoproto}
-go get golang.org/x/tools/cmd/goimports
+go get -u github.com/gogo/protobuf/{proto,protoc-gen-gogo,gogoproto}
+go get -u golang.org/x/tools/cmd/goimports
 pushd "${GOGOPROTO_ROOT}"
 	git reset --hard "${SHA}"
 	make install