Force pip==21.1.3 to avoid resolver issues in 21.2.1
Force pip==21.1.3 to avoid resolver issues in 21.2.1

When freshly installing dependencies, the 21.2.1 dependency resolver
takes several hours to try to complete and either crashes or is
canceled when it exceeds the maximum 6 hour run time.

Charcoal-SE/SmokeDetector,Charcoal-SE/SmokeDetector