tests: drop python 2.7 support

.gitlab-ci.yml

@@ -9,10 +9,5 @@ check-manifest:
 flake8:
   script: tox -e flake8
 
-py27:
-  script: tox -e py27
-
 py3:
   script: tox -e py3
-
-

tox.ini

 [tox]
-envlist = py27,py3,flake8,check-manifest
-
-[testenv:py27]
-deps=
-  cubicweb<3.27
-  -rdev-requirements.txt
-commands =
-  {envpython} -m pytest {posargs}
+envlist = py3,flake8,check-manifest
 
 [testenv]
 deps =