Dropped support for Python 2

Commits

d73b0a1: Fixing workflow (German Lashevich)
af6c223: Replace yes by echo (German Lashevich)
cb17826: Enhance test script output (German Lashevich)
bb5cd4a: Do not run test script during docker build (German Lashevich)
a4ed660: Provide task command with empty input to avoid waiting (German Lashevich)
ccfa86a: Check return code instead of stderr output (German Lashevich)
22169d2: Add more debug logging (German Lashevich)
e77a4dd: Remove buggy exit.on.missing.db override and specify verbose mode explicitly (German Lashevich)
a16ca86: Drop support for Python 2 (German Lashevich)
c34ab6f: Remove outdated docs (German Lashevich)
7949fb3: Bump version to 2.0.0 (German Lashevich)