Use Pipenv to manage requirements
pipenv is a tool for managing application dependencies.
The Pipfile was generated from the existing
requirements.txt (using pipenv install),
and the requirements.txt were generated back
from the Pipfile[.lock]
(using pipenv lock -r > requirements.txt)
Same thing for the requirements-test.txt file
(renamed to requirements-dev for convention)
This will make it easier to bump dependencies.