Minor and temporary (?) test updates for Python 3.12.
6.0
Add support for more `local` implementation.
5.0
- switch to `pyproject.toml` - require Python *3.10+*
4.0
- add `max_using_delay` for warnings. - add `with` support to both `Pool` and `Proxy` classes. - add module-specific exceptions: `PoolException`, `ProxyException`.
3.0
- wait for available objects when `max_size` is reached. - add `min_size` parameter to `Proxy`.