* New package: py-librosa

This PR adds the py-librosa package, along with new dependency packages
and some updates of existing dependency packages.

- new package: py-audioread
- new package: py-resampy
- new package: py-soundfile
- update package: py-numba
- update package: py-llvmlite

py-numba:
- add updated version
- adjust constraints

py-llvmlite:
- add updated version
- adjust constraints
- fix version specifications for llvm
- add environment function to set PIC

* Update var/spack/repos/builtin/packages/py-numba/package.py

Ah, yes, I see that `setuptools` is listed in the `install_requires` array. I missed that before.

Co-Authored-By: Adam J. Stewart <ajstewart426@gmail.com>

* Fix dependency

- Add dependency of py-soundfile depends on libsndfile
- Add new libsndfile package

* Add py-pytest-runner build dep

* Make numpy a variant for py-soundfile

Co-authored-by: Adam J. Stewart <ajstewart426@gmail.com>