build: integrate mypy-protobuf for stub generation

[jrtknauer]

The mypy-protobuf requirements [0] are not "hard" requirements, as earlier versions are simply untested. The listed requirement of protoc >= 4.21.8 is therefore not definitive, as with this commit protoc
version 3.4.0 successfully generated stubs with the plugin.

References:

[0] https://github.com/nipunn1313/mypy-protobuf#requirements-to-run-mypy-protobuf

[jrtknauer]

Example install and outputs:

$ sudo pip install .
Processing /home/jrtknauer/jrt/tmp/s2client-proto
  Preparing metadata (setup.py) ... done
Requirement already satisfied: mypy-protobuf in /usr/local/lib/python3.10/dist-packages (from s2clientprotocol==5.0.11.90136.0) (3.3.0)
Requirement already satisfied: protobuf in /usr/local/lib/python3.10/dist-packages (from s2clientprotocol==5.0.11.90136.0) (3.20.3)
Requirement already satisfied: types-protobuf>=3.19.12 in /usr/local/lib/python3.10/dist-packages (from mypy-protobuf->s2clientprotocol==5.0.11.90136.0) (4.23.0.1)
Building wheels for collected packages: s2clientprotocol
  Building wheel for s2clientprotocol (setup.py) ... done
  Created wheel for s2clientprotocol: filename=s2clientprotocol-5.0.11.90136.0-py3-none-any.whl size=55612 sha256=90e200f20d9b0393180da6378fe26dcaebf5afad7d4452fcb0bfa7f604bdaf17
  Stored in directory: /root/.cache/pip/wheels/a1/c7/ab/c94eff23fc8bc78833f5edc3a65a85c277da4d35fe39573367
Successfully built s2clientprotocol
Installing collected packages: s2clientprotocol
  Attempting uninstall: s2clientprotocol
    Found existing installation: s2clientprotocol 5.0.11.90136.0
    Uninstalling s2clientprotocol-5.0.11.90136.0:
      Successfully uninstalled s2clientprotocol-5.0.11.90136.0
Successfully installed s2clientprotocol-5.0.11.90136.0

$ ls -l s2clientprotocol
total 884
-rw-r--r-- 1 jrtknauer jrtknauer      0 Jun 27 16:17 __init__.py
drwxr-xr-x 2 jrtknauer jrtknauer   4096 Jun 27 16:21 __pycache__
-rw-r--r-- 1 jrtknauer jrtknauer    952 Jun 27 16:17 build.py
-rw-r--r-- 1 jrtknauer jrtknauer   1217 Jun 27 16:17 common.proto
-rw-r--r-- 1 root      root       13208 Jun 27 16:21 common_pb2.py
-rw-r--r-- 1 root      root        6404 Jun 27 16:21 common_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   5435 Jun 27 16:17 data.proto
-rw-r--r-- 1 root      root       33259 Jun 27 16:21 data_pb2.py
-rw-r--r-- 1 root      root       18791 Jun 27 16:21 data_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   2677 Jun 27 16:17 debug.proto
-rw-r--r-- 1 root      root       37032 Jun 27 16:21 debug_pb2.py
-rw-r--r-- 1 root      root       18087 Jun 27 16:21 debug_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   6515 Jun 27 16:17 error.proto
-rw-r--r-- 1 root      root       45236 Jun 27 16:21 error_pb2.py
-rw-r--r-- 1 root      root       24198 Jun 27 16:21 error_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   1645 Jun 27 16:17 query.proto
-rw-r--r-- 1 root      root       17931 Jun 27 16:21 query_pb2.py
-rw-r--r-- 1 root      root        8942 Jun 27 16:21 query_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   5768 Jun 27 16:17 raw.proto
-rw-r--r-- 1 root      root       59938 Jun 27 16:21 raw_pb2.py
-rw-r--r-- 1 root      root       31464 Jun 27 16:21 raw_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer  27351 Jun 27 16:17 sc2api.proto
-rw-r--r-- 1 root      root      182998 Jun 27 16:21 sc2api_pb2.py
-rw-r--r-- 1 root      root       94695 Jun 27 16:21 sc2api_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   5481 Jun 27 16:17 score.proto
-rw-r--r-- 1 root      root       22401 Jun 27 16:21 score_pb2.py
-rw-r--r-- 1 root      root       15458 Jun 27 16:21 score_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   5926 Jun 27 16:17 spatial.proto
-rw-r--r-- 1 root      root       41026 Jun 27 16:21 spatial_pb2.py
-rw-r--r-- 1 root      root       23206 Jun 27 16:21 spatial_pb2.pyi
-rw-r--r-- 1 jrtknauer jrtknauer   4136 Jun 27 16:17 ui.proto
-rw-r--r-- 1 root      root       44755 Jun 27 16:21 ui_pb2.py
-rw-r--r-- 1 root      root       24260 Jun 27 16:21 ui_pb2.pyi

However, what information I do not have is what environment is building the package for publication. mypy-protobuf has a hard execution requirement for Python 3.7 and greater - and the setup.py has not been updated to reflect Python versions since Python 3.4. If the environment is unable to support adoption of generating Python stubs, I will default to publishing the generated stubs to typeshed instead.

[Avasam]

Might be a good idea to add a py.typed marker as well https://peps.python.org/pep-0561/#packaging-type-information
Which also needs to be explicitly added to setup.py for anyone not using setuptools>=69