Hierarchicalforecast

What's Changed
* [FIX] 1 and 2 in https://github.com/Nixtla/hierarchicalforecast/pull/4
* feat: return tags in https://github.com/Nixtla/hierarchicalforecast/pull/5
* feat: add hierarchical evaluator in https://github.com/Nixtla/hierarchicalforecast/pull/6
* fix: add overall evaluation in https://github.com/Nixtla/hierarchicalforecast/pull/8
* [FIX/FEAT] Add strictly hierarchical test for top down methods in https://github.com/Nixtla/hierarchicalforecast/pull/9
* [FEAT] MiddleOut method in https://github.com/Nixtla/hierarchicalforecast/pull/10
* [FEAT] README by https://github.com/Nixtla/hierarchicalforecast/pull/11
* [FEAT] homogenize inputs across methods in https://github.com/Nixtla/hierarchicalforecast/pull/14

**Full Changelog**: https://github.com/Nixtla/hierarchicalforecast/compare/v0.0.4...v0.0.5

Return `S_df` object.
**Full Changelog**: https://github.com/Nixtla/hierarchicalforecast/compare/v0.0.3...v0.0.4

Adding classes for reconciliation methods and minor bug fixes.
**Full Changelog**: https://github.com/Nixtla/hierarchicalforecast/compare/v0.0.2...v0.0.3

Modular version of `HierarchicalForecast`.

**Full Changelog**: https://github.com/Nixtla/hierarchicalforecast/compare/v0.0.1...v0.0.2

The first version of `HierarchicalForecast` 🎉 🌮 🐍