Pyversion-info

- Support platformdirs v4.0
- Migrated from setuptools to hatch
- Support cachecontrol v0.14

- Support Python 3.12
- Correct the order of results returned by `PyPyVersionInfo.supported_cpython_series()`

- Support platformdirs v3.0
- Update pydantic to v2.0

- Support Python 3.11
- Support cachecontrol 0.13

- Use pydantic internally for parsing & validating version databases
- `eol_date()` and `is_eol()` now accept major and micro versions
- The `show` command now outputs the EOL date and EOL state for all CPython version levels

- Support Python 3.10
- Drop support for Python 3.6
- Support for fetching information on PyPy versions has been added. With it come the following changes:
- The schema used by the database (and thus the URL for the default database) has been modified
- `PyVersionInfo` has been renamed to `CPythonVersionInfo`
- A new `PyPyVersionInfo` class has been added
- A new `VersionDatabase` class has been added, containing a `CPythonVersionInfo` instance and a `PyPyVersionInfo` instance
- `get_pyversion_info()` is now `VersionDatabase.fetch()`
- The command-line interface now takes a `--pypy` option for showing details about PyPy versions
- The `unreleased` argument to `major_versions()`, `minor_versions()`, `micro_versions()`, and `subversions()` has been removed; the methods now return all known versions, released & unreleased
- `release_date()` now returns `None` for any known version whose release date is unknown, whether it's been released yet or not. Use `is_released()` to determine whether such a version has been released.
- `eol_date()` now returns `None` for any known version whose EOL date is unknown, whether it's EOL yet or not. Use `is_eol()` to determine whether such a version has reached end-of-life.
- Moved documentation from README file to a Read the Docs site