Require pytest >= 4.6
Require pytest >= 4.6

Travis's default python archive for python < 3.8 includes pytest 4.1, which is
incompatible with the latest pytest-cov (v2.8.1). This has caused recent
CI builds to fail.

johnzimm/xx-puppetboard,johnzimm/xx-puppetboard,voxpupuli/puppetboard,voxpupuli/puppetboard,puppet-community/puppetboard,johnzimm/puppetboard,puppet-community/puppetboard,johnzimm/xx-puppetboard,voxpupuli/puppetboard,johnzimm/puppetboard,johnzimm/puppetboard,puppet-community/puppetboard,johnzimm/xx-puppetboard