Allow pytestmain factor to fail, since pytest introduced an incompatible change

Author: youtux

tox.ini

@@ -7,6 +7,8 @@ envlist = py{3.9,3.10,3.11,3.12,3.13}-pytest{7.3,7.4,8.0,8.1,8.2,8.3,latest,main
 [testenv]
 parallel_show_output = true
 commands = coverage run -m pytest {posargs:tests}
+ignore_outcome =
+    pytestmain: True
 deps =
     pytestlatest: pytest
     pytestmain: git+https://github.com/pytest-dev/pytest.git@main
@@ -22,6 +24,7 @@ deps =
 
     coverage[toml]
 
+
 [testenv:mypy]
 allowlist_externals = mypy
 commands = mypy {posargs:.}