Decopatch

- `function_decorator` now has proper type hints. This is a first step towards fixing [22](https://github.com/smarie/python-decopatch/issues/22). PR [#23](https://github.com/smarie/python-decopatch/pull/23) by [last-partizan](https://github.com/last-partizan).

1.4.9 - New layout and CI + Compatibility fixes.

- Enabling the "stack introspection" beta feature with `enable_stack_introspection=True` now raises an explicit `NotImplementedError` on python 3.8+. Fixed [26](https://github.com/smarie/python-decopatch/issues/26).

- Migrated to the new project layout with nox, github-actions and separation of `src` and `tests`. Fixed test suite with `pytest-cases>=3`. Fixed [24](https://github.com/smarie/python-decopatch/issues/24) and [#20](https://github.com/smarie/python-decopatch/issues/20).

- packaging improvements: set the "universal wheel" flag to 1, and cleaned up the `setup.py`. In particular removed dependency to `six` for setup and added `py.typed` file, as well as set the `zip_safe` flag to False. Removed tests folder from package. Fixes [19](https://github.com/smarie/python-decopatch/issues/19)

[raddessi](https://github.com/raddessi) added a `pyproject.toml` - thanks! Fixed [pytest-cases#65](https://github.com/smarie/python-pytest-cases/issues/65).

Fixed decorated object injection issue when var-positional arguments are located before it in the signature. Fixed [14](https://github.com/smarie/python-decopatch/issues/14).

Added `__version__` attribute to comply with PEP396, following [this guide](https://smarie.github.io/python-getversion/#package-versioning-best-practices). Fixes [15](https://github.com/smarie/python-decopatch/issues/15).

PyPI supports markdown via `long_description_content_type`: pypandoc is not required anymore. Thanks [minrk](https://github.com/smarie/python-makefun/pull/44)!

* Huge performance improvement for the `enable_stack_introspection=True` mode. It also now supports classes correctly.

1.4.3 - Bugfix in nested mode under python 2

In python 2, when nested mode was used in a context where the signature contains a var-positional argument, a `TypeError` was raised ; this is now fixed. Fixes [13](https://github.com/smarie/python-decopatch/issues/13).

1.4.2 - Bugfix in flat mode under python 2

In python 2, when flat mode was used in a context where the signature contains a var-positional argument, the arguments were not correctly injected. Fixes [12](https://github.com/smarie/python-decopatch/issues/12).