README: Update Debian package status

Closes #17
3 jobs for master in 1 minute and 14 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Linting
passed #101423
mypy

00:00:30

passed #101422
pyflakes

00:00:21

 
  Test
passed #101424
tests:debian

00:00:42

94.0%