1. Added Signals functionality (Feature neutral corr from Numerai diagnostics for `NumeraiSignalsEvaluator`, `PandasDataReader`, `TickerMapper` and `SignalsTargetProcessor`.
2. Turn `Key` into normal class to avoid `dataclass` related bugs. No breaking changes were introduced.
What's Changed
* Features/signals diagnostics by crowdcent in https://github.com/crowdcent/numerblox/pull/88
* v0.2.19 by crowdcent in https://github.com/crowdcent/numerblox/pull/89
* TickerMapper by crowdcent in https://github.com/crowdcent/numerblox/pull/91
* Key to dataclass and remove post init print by crowdcent in https://github.com/crowdcent/numerblox/pull/92
* Feature/signals target processor by crowdcent in https://github.com/crowdcent/numerblox/pull/93
* v0.3.0 by crowdcent in https://github.com/crowdcent/numerblox/pull/94
**Full Changelog**: https://github.com/crowdcent/numerblox/compare/v0.2.18...v0.3.0