[8.1.x] doc: add versionadded to ExceptionInfo.group_contains (#12142)

Co-authored-by: Sebastian Meyer <[email protected]>

src/_pytest/_code/code.py

@@ -788,6 +788,8 @@ def group_contains(
             If `None`, will search for a matching exception at any nesting depth.
             If >= 1, will only match an exception if it's at the specified depth (depth = 1 being
             the exceptions contained within the topmost exception group).
+
+        .. versionadded:: 8.0
         """
         msg = "Captured exception is not an instance of `BaseExceptionGroup`"
         assert isinstance(self.value, BaseExceptionGroup), msg