Pylandau

This release adds support for numpy 1.21 since 1.22 is not supported by numba (yet). Before, pylandau dependencies and numba dependencies could not be resolved if both packages are installed.
From now on, the C code will be compiled at installation to build against the specific numpy version the user is running.

What's Changed
* Numba support in pylandau environment by cbespin in https://github.com/SiLab-Bonn/pylandau/pull/23

**Full Changelog**: https://github.com/SiLab-Bonn/pylandau/compare/v2.2.0...v2.2.1

This release adds functionality to set eta < 1. It also comes with a new release on [pypi.org](https://pypi.org/project/pylandau/).

Support for python < 3.8 was dropped due to scipy and numpy dropping support for python3.7 as well.

This release adds support for python versions 3.7 to 3.9 and is tested on Ubuntu, Windows and macOS.

What's Changed
* Allow building from a Pipfile or requirements.txt by henryiii in https://github.com/SiLab-Bonn/pylandau/pull/7
* py3.7 - py3.9 support by ChristianBesp in https://github.com/SiLab-Bonn/pylandau/pull/19

New Contributors
* henryiii made their first contribution in https://github.com/SiLab-Bonn/pylandau/pull/7
* ChristianBesp made their first contribution in https://github.com/SiLab-Bonn/pylandau/pull/19

**Full Changelog**: https://github.com/SiLab-Bonn/pylandau/compare/2.1.0...v2.1.2

- More stable fitting, the convergence issues from the last releases are gone
- More precise amplitude and MPV estimation
- New example how to determine the MPV asymmetric errors taking fit correlations into account. This is the only existing correct example how to do this. It is not possible with the CERN ROOT Langau definition.

The scaling of the amplitude did not work for pylangau. Fixed in this comit.

- API change: the functions that are no PDF are definced in a way that the MPV can be given
- due to the last API change of the package the version is increased to 2.0.0