Old versions of Requests cause errors

[dscorbett]

Observed behavior

Running Font Bakery with an old version of Requests raises an error. Version 2.19 is the oldest that works with all versions of Python that Font Bakery supports.

Expected behavior

Font Bakery’s pyproject.toml should restrict the dependency to versions that always work: requests >= 2.19. (This could be made more precise with environment markers, since some older Requests versions work in some older Python versions.)

Resources and steps needed to reproduce

pip install requests==0.2.0 fontbakery==0.12.6
touch placeholder.otf
fontbakery check-universal -c com.google.fonts/check/fontbakery_version placeholder.otf

[felipesanches]

Please, send a PR with this proposed fix.