Go generation not working

[gbarnett-hz]

From README.md the language go is a supported (or at least enabled option):

./generator.py [-r ROOT_DIRECTORY] [-l LANGUAGE] [-p PROTOCOL_DEFS_PATH] [-o OUTPUT_DIRECTORY] [-n NAMESPACE] [-b BINARY_OUTPUT_DIR] [-t TEST_OUTPUT_DIR] [--no-binary] [--no-id-check]

where

* `ROOT_DIRECTORY` is the root folder for the generated codecs. If left empty, default value is set to `./output/[LANGUAGE]`.

* `LANGUAGE` is one of
    * `java` : Java
    * `cpp` : C++
    * `cs` : C#
    * `py` : Python
    * `ts` : TypeScript
    * `go` : Go

But when one does the following:

./generator.py -l go

We are told that go is invalid choice.

usage: generator.py [-h] [-r ROOT_DIRECTORY] [-l LANGUAGE] [-p PROTOCOL_DEFS_PATH] [-o OUTPUT_DIRECTORY] [-n NAMESPACE] [-b BINARY_OUTPUT_DIRECTORY]
                    [-t TEST_OUTPUT_DIRECTORY] [--no-binary] [--no-id-check]
generator.py: error: argument -l/--lang: invalid choice: 'go' (choose from 'java', 'cpp', 'cs', 'py', 'ts', 'md')

It seems that documentation is not up-to-date or generate.sh script is not working as expected. I believe it's probably the former.