instructions to build wheel from source not working

[gl-yziquel]

Hi.

The build instructions to build the wheel from source given in the readme file do not work.

bazel build --copt=-O3 --copt=-march=native :pip_pkg
mkdir -p dist && ./bazel-bin/pip_pkg dist

The build complains about a missing version.py file. This is because the paths in pip_pkg.sh are messed up. Seems no one builds from source these days (to my utter dismay) and this code has bit rot.

[gl-yziquel]

The PR above seems to fix paths and generate a wheel, that does install with pip install.

However, I have little experience with tensorflow-probability, so I do not know how functional that wheel is. I'll try it out...