Environs

Features:

- `Env.timedelta` can parse [GEP-2257](https://gateway-api.sigs.k8s.io/geps/gep-2257/)
duration strings ([366](https://github.com/sloria/environs/pull/366)).
Thanks [ddelange](https://github.com/ddelange) for the PR.

Features:

- Add `return_path` argument to `Env.read_env` to return the path of the
parsed file ([362](https://github.com/sloria/environs/issues/362)).
Thanks [senese](https://github.com/senese) for the suggestion and PR.
NOTE: This is added as a backwards-compatible change that is scheduled to be
removed in 12.0.0. The path will stored as an attribute of `Env`.

Fixes:

- Prevent `DeprecationWarning` getting raised by marshmallow 3.21.0 (:issue:`333`).

Other changes:

- Remove `subcast_key` argument of `env.dict`. Use `subcast_keys` instead.
- Bump minimum required marshmallow version to 3.13.0.
- Remove `missing` argument from `Env` methods. Use `default` instead.
- Remove `subcast` argument from `Env` methods that don't use it.
- _Backwards-incompatible_: Remove `environs.__version__` variable.
Use `importlib.metadata.version("environs")` instead.

Features:

- `Env.__repr__` and `Env.__str__` no longer display environment variables, to prevent accidental exfiltration of sensitive data ([292](https://github.com/sloria/environs/issues/292)).
Thanks [mro-rhansen2](https://github.com/mro-rhansen2) for the suggestion.

Bug fixes:

- Fix passing `None` as default to `env.list` ([298](https://github.com/sloria/environs/issues/298)).
Thanks [lucas-bremond](https://github.com/lucas-bremond) for reporting.

Features:

- `env.read_env` returns `False` if file not found ([294](https://github.com/sloria/environs/issues/294)).
Thanks [rptaylor](https://github.com/rptaylor) for the suggestion.

Features:

- Allow `default` for `env.json` to be a `dict` or `list` ([240](https://github.com/sloria/environs/pull/240)).
Thanks [tomgrin10](https://github.com/tomgrin10) and [bvanelli](https://github.com/bvanelli) for the PRs.

Other changes:

- Test against Python 3.12.