Put back 2.7 and 3.5 in tests

Author: andrivet

tox.ini

@@ -4,12 +4,14 @@
 envlist =
     clean,
     check,
-    {py36,py37,py38,py39,py310},
+    {py27,py35,py36,py38,py39,py310},
     report,
     docs
 
 [gh-actions]
 python =
+  2.7: py27
+  3.5: py35
   3.6: py36
   3.7: py37
   3.8: py38
@@ -23,12 +25,16 @@ setenv =
 passenv =
     *
 usedevelop = false
-deps = -rrequirements-dev.txt
+deps =
+    pytest
+    nose
+    future
+    enum-compat
+    coverage
 commands =
     pytest -vv tests
     coverage run -m pytest tests
 
-
 [testenv:spell]
 setenv =
     SPELLCHECK=1