Kloppy

Github issues closed:

- Enrich events with state ([48](https://github.com/PySport/kloppy/issues/48))

Other pull requested merged:

- Chaining of methods ([59](https://github.com/PySport/kloppy/pull/59))

Github issues closed
- to_pandas fails for Opta data when trying to read player_id ([57](https://github.com/PySport/kloppy/issues/57)

Other pull requests merged:
- Fix error in naming of inputs to metrica json serializer in helper ([56](https://github.com/PySport/kloppy/pull/56))

Github issues closed:

- Add provider to dataset ([36](https://github.com/PySport/kloppy/issues/36))
- Adding a data type type to the datasets ([45](https://github.com/PySport/kloppy/issues/45))

Other pull requests merged:

- Add Metrics Json event serializer ([44](https://github.com/PySport/kloppy/pull/44))
- Code formatting & typos in docs ([39](https://github.com/PySport/kloppy/pull/39), [#40](https://github.com/PySport/kloppy/pull/40))

- Add metadata models (bdagnino)
- Move docs to https://kloppy.pysport.org/ (pratikthanki & koenvo)

- Fix to_pandas for Opta event data

- Fix in readme (rjtavares)
- Add additional_columns to to_pandas (rjtavares)