Fix an issue with old tox version

tox.ini

@@ -59,9 +59,9 @@ deps =
     pytest-cov>=4,<7
     pytest-describe>=2,<3
     pytest-timeout>=2,<3
-    py3{6,7,8,9}, pypy39: typing-extensions>=4.2,<5
+    py3{6,7,8,9},pypy39: typing-extensions>=4.1,<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
-    py3{6,7,8,9,10,11,13}, pypy3{9,10}: pytest tests {posargs}
+    py3{6,7,8,9,10,11,13},pypy3{9,10}: pytest tests {posargs}
     py312: pytest tests {posargs: --cov-report=term-missing --cov=graphql --cov=tests --cov-fail-under=100}