pipenv version dependency

[elray1]

At some point, a pipenv update resulted in the validations code failing with an inability for python scripts to load the certifi package, which was installed as a system library but was not being found when python was trying to load it. I manually set the version of pipenv back to a release from last week here and the validations seem to run OK now.

This is not a very ideal long term solution because we'll fall behind in the pipenv versions. I don't understand what was happening well enough to offer any other alternatives, though. Might be worth just putting it on our radar to check on this in a few weeks, in case this turns out to be a bug introduced in pipenv that is solved?