Update tox config [ci skip]

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 distshare={homedir}/.tox/distshare
-envlist=linters,py38-xdist,py38-pytest-latest,py38
+envlist=linters,py{38,39,310}-xdist,py{38,39,310}-pytest-latest,py{38,39,310}
 skip_missing_interpreters = true
 
 [testenv]
@@ -11,7 +11,7 @@ deps =
 passenv = DISPLAY
 
 [testenv:linters]
-basepython=python3.8
+basepython=python3.10
 commands={[testenv]commands} pytest_splinter --black
 
 [testenv:coveralls]
@@ -23,17 +23,15 @@ commands=
     coverage report -m
     coveralls
 
-[testenv:py38-xdist]
-basepython=python3.8
+[testenv:xdist]
 deps =
     {[testenv]deps}
     pytest-xdist
 commands=
   py.test pytest_splinter tests -n1 -rfsxX \
         --junitxml={envlogdir}/junit-{envname}.xml
 
-[testenv:py38-pytest-latest]
-basepython=python3.8
+[testenv:pytest-latest]
 deps =
     {[testenv]deps}
     git+https://github.com/pytest-dev/py.git#egg=py
@@ -44,10 +42,6 @@ addopts = -vvl -r w
 
 [gh-actions]
 python =
-    2.7: py27
-    3.5: py35
-    3.6: py36
-    3.7: py37
     3.8: py38
     3.9: py39
     3.10: py310