Fixed test with pytest 8.1+

Author: Sylvain MARIE

src/pytest_cases/common_pytest_marks.py

@@ -44,6 +44,7 @@
 PYTEST7_OR_GREATER = PYTEST_VERSION >= Version('7.0.0')
 PYTEST71_OR_GREATER = PYTEST_VERSION >= Version('7.1.0')
 PYTEST8_OR_GREATER = PYTEST_VERSION >= Version('8.0.0')
+PYTEST81_OR_GREATER = PYTEST_VERSION >= Version('8.1.0')
 PYTEST811 = PYTEST_VERSION == Version('8.1.1')