Just run make and the generated protos will be updated.
If the protoc compiler is confused by the map type, you are probably running version of protoc < v3.0. You can check with protoc --version. See below for updating your protoc version.
Grab protoc-3.2.0-linux-x86_64.zip release from https://github.com/google/protobuf/releases/tag/v3.2.0
Newer releases of protoc are not compatible with the current version of protobuf python package installed in requirements.txt at the time of this writing.
Extract bin/protoc from the release and copy it into /usr/bin/protoc. Give it execute permissions.
Check the new version with protoc --version.