feat: drop python2

--HG--
branch : seda21
4 jobs for !22 with topic/seda21/drop-python2 in 32 seconds (queued for 28 seconds)
detached
Status Job ID Name Coverage
  Lint
passed #336538
check-manifest

00:00:28

failed #336537
flake8

00:00:32

 
  Tests
skipped #336539
py27
skipped #336540
py3
 
Name Stage Failure
failed
flake8 Lint
ERROR: InvocationError for command /builds/cubicweb/cubes/seda/.tox/flake8/bin/flake8 . (exited with code 1)
___________________________________ summary ____________________________________
ERROR: flake8: commands failed
Uploading artifacts for failed job
Uploading artifacts...
gl-code-quality-report.json: found 1 matching files and directories

Uploading artifacts as "codequality" to coordinator... ok
id=336537 responseStatus=201 Created token=rKewQxSH
Cleaning up file based variables
ERROR: Job failed: command terminated with exit code 1