Backport gettext.pgettext and drop Python 3.8 requirement

Fixes #68.
3 jobs for 68-backport-pgettext in 3 minutes and 30 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #6044
pycodestyle

00:01:20

passed #6045
pylint

00:02:09

manual #6046
allowed to fail manual
pytest