pip install does not install shiboken2-generator

I installed PySide2 5.12.0 using 'pip install PySide2', which installed PySide2 and Shiboken2 but did not install Shiboken2-generator. This behaves differently from building and installing PySide2 from source, which also installs Shiboken2-generator. I am not sure if the pip install behavior is intentional or not, so I created this bug.