Add py.typed file and distribute it upon installation

[felixdivo]

This should allow downstream packages and "end users" to use type checkers more easily.

Fixes #1340.

[felixdivo]

@rumpelsepp Do you mind checking if this change works for you? This should work:

pip uninstall python-can
pip install git+https://github.com/felixdivo/python-can.git@add-py.typed-file-marker

[codecov]

Codecov Report

Merging #1344 (15013a6) into develop (5bca2d7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #1344   +/-   ##
========================================
  Coverage    66.01%   66.01%           
========================================
  Files           86       86           
  Lines         8960     8960           
========================================
  Hits          5915     5915           
  Misses        3045     3045           

[felixdivo]

I guess that the failing test has nothing to do with the change.

[zariiii9003]

Is the setup.py entry sufficient for it to be included in the source distribution?

[felixdivo]

Is the setup.py entry sufficient for it to be included in the source distribution?

Yes, that appears to work. I opened a python:3 Docker image, produced a source distribution with python setup.py sdist bdist_wheel and then inspected the generated distribution file dist/python-can-4.0.0.tar.gz. It contains the marker file.