Change pytest deprecation warnings into errors for 6.0 release (#7362)

Co-authored-by: Hugo van Kemenade <hugovk@users.noreply.github.com>

testing/conftest.py

@@ -116,11 +116,11 @@ def dummy_yaml_custom_test(testdir):
 
         def pytest_collect_file(parent, path):
             if path.ext == ".yaml" and path.basename.startswith("test"):
-                return YamlFile(path, parent)
+                return YamlFile.from_parent(fspath=path, parent=parent)
 
         class YamlFile(pytest.File):
             def collect(self):
-                yield YamlItem(self.fspath.basename, self)
+                yield YamlItem.from_parent(name=self.fspath.basename, parent=self)
 
         class YamlItem(pytest.Item):
             def runtest(self):