Error importing plugin "classes.contrib.mypy.classes_plugin" cannot import name 'union_items' from 'mypy.types'

# Bug report

## What's wrong

I am hitting the error on a clean installation with python3.11 on MacOS.
```python
Python 3.11.1 (main, Dec 12 2022, 14:17:59) [Clang 14.0.0 (clang-1400.0.29.202)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import classes.contrib.mypy.classes_plugin
Traceback (most recent call last):
File "", line 1, in
File "/Users/uname/PycharmProjects/sandbox/.venv/lib/python3.11/site-packages/classes/contrib/mypy/classes_plugin.py", line 33, in
from classes.contrib.mypy.features import associated_type, supports, typeclass
File "/Users/uname/PycharmProjects/sandbox/.venv/lib/python3.11/site-packages/classes/contrib/mypy/features/typeclass.py", line 17, in
from classes.contrib.mypy.typeops import (
File "/Users/uname/PycharmProjects/sandbox/.venv/lib/python3.11/site-packages/classes/contrib/mypy/typeops/call_signatures.py", line 9, in
from mypy.types import TypeVarType, union_items
ImportError: cannot import name 'union_items' from 'mypy.types' (/Users/uname/PycharmProjects/sandbox/.venv/lib/python3.11/site-packages/mypy/types.cpython-311-darwin.so)
```

## How is that should be

No errors

## System information

- `python` version:
- `classes` version:
- `mypy` version: