Don't fall back to importing from `py.io`

We require pytest>=6.2; `_pytest._io.TerminalWriter` exists since
6.0.0rc1. See the previous commit for details.

src/pytest_bdd/generation.py

@@ -5,13 +5,9 @@ import itertools
 import os.path
 from typing import TYPE_CHECKING, cast
 
+from _pytest._io import TerminalWriter
 from mako.lookup import TemplateLookup
 
-try:
-    from _pytest._io import TerminalWriter
-except ImportError:
-    from py.io import TerminalWriter
-
 from .feature import get_features
 from .scenario import inject_fixturedefs_for_step, make_python_docstring, make_python_name, make_string_literal
 from .steps import get_step_fixture_name