Building and getting Keel working on PureOS and Debian Stretch succeeded therefore moving to Django 1.11.18.
I'm also removing Pipfile.lock as per Pipenv recommendations when targeting multiple Python versions.
Debian Stretch uses (as of today) 3.5 while PureOS uses 3.7
Signed-off-by: Birin Sanchez birin.sanchez@puri.sm