pyside2-uic is not executable on windows

pyside2-uic is a python script:

(pyside-setup/sources/pyside2-tools/pyside2-uic):

#!/usr/bin/env python
# This file is part of the PySide project.

On unix it relies on the shebang mecanism to be executable by the shell

On windows, the shell cannot find it when we issue the command "pyside2-uic".

A possible workaround is to install a pyside2-uic.bat file which runs the script through python and passing the arguments:

python %~dp0pyside2-uic %*

(also affects 1.2.x branch, we use this workaround in https://github.com/conda-forge/pyside-feedstock and in the pyside2 alpha package to be announced).