2to3 dependency support was removed in python 3.13 breaking package functionality

Using pyannotate 1.2.0, Python 3.13.1 (main, Dec 4 2024, 08:54:14) [GCC 11.4.0] on linux

- see the maintainers deprecation notice [https://docs.python.org/3.12/library/2to3.html](url)

Code example:

```
from pyannotate_runtime import collect_types

collect_types.init_types_collection()

if __name__ == "__main__":
collect_types.start()
runner = Runner()
asyncio.run(runner.run())
collect_types.stop()
collect_types.dump_stats("example-types.dump")
```

The error:

```
(venv) void@null » pyannotate --type-info example-types.dump --py3 -w main.py
Traceback (most recent call last):
File "/home/void/my_project/venv/bin/pyannotate", line 5, in
from pyannotate_tools.annotations.__main__ import main
File "/home/void/my_project/venv/lib/python3.13/site-packages/pyannotate_tools/annotations/__main__.py", line 9, in
from lib2to3.main import StdoutRefactoringTool
ModuleNotFoundError: No module named 'lib2to3'

```