Update pip package of urdf2casadi on PyPI

[maximvochten]

Thank you for providing this package!

I would like to include urdf2casadi in another package through PyPI. However the current version on PyPI (https://pypi.org/project/urdf2casadi/) still assumes a fixed version of CasADi (==3.5.5) which conflicts with my other package. I saw this dependency had been fixed in the source code here on GitHub (https://github.com/mahaarbo/urdf2casadi).

Would you be willing to update the urdf2casadi package on PyPI to the latest version of urdf2casadi on GitHub?