feat: advertise constraints in setup.py

[edx-requirements-bot]

Update setup.py to consider constraint files when creating the requires.txt file

Additional information from script execution

ARCHBOM-1772
Update setup.py to use constraint files when generating requirements files for packaging and distribution.
PR generated automatically with Jenkins job cleanup-python-code.

Old requirements file:

edx-opaque-keys>=2.0.0
six>=1.10.0

New requirements file:

edx-opaque-keys>=2.0.0
six>=1.10.0

Python code cleanup by the cleanup-python-code Jenkins job.

This pull request was generated by the cleanup-python-code Jenkins job, which ran

curl -sS "https://raw.githubusercontent.com/edx/edx-cookiecutters/f8f4c9c5162d4b4ee7def4f46ab8cd31071d93db/scripts/update_setup_py.sh" > update_setup_py.sh
bash update_setup_py.sh

The following packages were installed:
semgrep,isort

[nedbat]

This is currently failing due to a strange pip== pin in the travis.yml file. This repo will be converted to GitHub Actions, and we can rebase this pull request then.