Cem

What's Changed
* Update README.md by lewisbails in https://github.com/lewisbails/cem/pull/22
* BREAKING CHANGE: Remove option to import `match` and `coarsen` functions from the top-level package.


**Full Changelog**: https://github.com/lewisbails/cem/compare/1.0.0...1.1.0

What's Changed
* Major refactor. Remove CEM class. Update tests by lewisbails in https://github.com/lewisbails/cem/pull/21


**Full Changelog**: https://github.com/lewisbails/cem/compare/0.1.9...1.0.0

* Update type hints

* Added documentation with github page
* Fixed docstrings
* Remove option to not pass a coarsening schema when using `CEM.match` method

* Add warnings for coarsening schemas that do not contain all continuous variables in the underlying data
* Add warnings for all-zero weights

* Switch to using poetry
* Drop official support for python <3.9
* Add more documentation