tox.ini: pin pytest==5.1.1 to workaround issue with caplog fixture on windows
tox.ini: pin pytest==5.1.1 to workaround issue with caplog fixture on windows

https://ci.appveyor.com/project/fonttools/fonttools/builds/27126458/job/iomtsu4prflws4xu

fonttools/fonttools,googlefonts/fonttools