Iso-week-date

What's Changed

* Extend `__add__` & `__sub__` to iterable(s) by FBruzzesi in https://github.com/FBruzzesi/iso-week-date/pull/59


**Full Changelog**: https://github.com/FBruzzesi/iso-week-date/compare/v1.0.0...v1.1.0

Breaking Changes

Renamed pandas and polars namespaces from `isoweek` to `iwd`.

Description

- Adds pandas Series and polars Series and Expr extensions (dedicated namespaces) to work directly with methods instead of functions. [documentation section](https://fbruzzesi.github.io/iso-week-date/user-guide/dataframe-modules/#extensions)
- Fixes type hinting (now mypy compliant 😁)

- Adds IsoWeek and IsoWeekDate `to_values` and `from_values` methods
- Adds pandas and polars functionalities for isoweekdate series (to datetime and from datetime)

- Introduces the `IsoWeekDate` class to work with "YYYY-WNN-D" format
- Refactors core functionalities into an abstract base class and multiple mixin's