Fix and simplify tox.ini

Author: Cito

tox.ini

@@ -58,9 +58,9 @@ deps =
     pytest-cov>=4,<6
     pytest-describe>=2,<3
     pytest-timeout>=2,<3
-    py36,py37,38,py39,py310: typing-extensions>=4,<5
+    py3{6,7,8,9}, pypy39: typing-extensions>=4,<5
 commands =
     # to also run the time-consuming tests: tox -e py311 -- --run-slow
     # to run the benchmarks: tox -e py311 -- -k benchmarks --benchmark-enable
-    py37,py38,py39,py310,py311,pypy39,pypy310: pytest tests {posargs}
+    py3{6,7,8,9,10,11}, pypy3{9,10}: pytest tests {posargs}
     py312: pytest tests {posargs: --cov-report=term-missing --cov=graphql --cov=tests --cov-fail-under=100}