Add function 'add_value' (#17)

* Add function to add_value to cpacs and corresponding test

* Update version

fix import

Add rotorcraft configuration (#16)

* Add rotorcraft and corresponding test

* update version

Accept either string or Path object and update env (#15)

* Typo ref_lenght -> ref_length

* Accept either Path of str

* Update conda env

* black update

* Use Mambaforge and cache remove windows

* Windows pytest in a separate file

* Disable Windows workflow (not working for now)

v0.0.5