Revert GitHub Actions and Tox changes.

We can only reproduce this on specific Python 3.10.x patch versions, but we can't easily test those in CI. Give up the attempt.

.github/workflows/main.yml

@@ -62,7 +62,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu, windows]
-        python-version: ['3.8', '3.9', 3.10.8, '3.10', '3.11', '3.12']
+        python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
 
     steps:
     - uses: actions/checkout@v4

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 3.14.0
-envlist = py38, py39, py3108, py310, py311, py312, pytest-min, docs
+envlist = py38, py39, py310, py311, py312, pytest-min, docs
 isolated_build = true
 passenv =
     CI
@@ -25,14 +25,6 @@ commands = make test
 allowlist_externals =
     make
 
-[testenv:py3108]
-# Python 3.10.8 is the most recent version that triggers
-# https://github.com/pytest-dev/pytest-asyncio/issues/757.
-#
-# We need to set basepython explicitly here because if we just added "py3108" to
-# envlist, tox would interpret that as "py310".
-basepython = python3.10.8
-
 [testenv:docs]
 extras = docs
 deps =
@@ -47,7 +39,6 @@ allowlist_externals =
 python =
     3.8: py38, pytest-min
     3.9: py39
-    3.10.8: py3108
     3.10: py310
     3.11: py311
     3.12: py312