REG->6.2.0: QIcon.addPixmap(str) no longer works

Calling QIcon.addPixmap(str) no longer works, producing:

TypeError: 'QIcon.addPixmap' called with wrong argument types:
QIcon.addPixmap(str)
Supported signatures:
QIcon.addPixmap(Union[QPixmap,QImage, str],
QIcon.Mode =QIcon.Mode.Normal,
QIcon.State =QIcon.State.Off)

This was caused by "pathlib: support all cases which are found in the examples"
10abd17ffb8826e4aa5861f89642c46c47b641a8 https://codereview.qt-project.org/c/pyside/pyside-setup/+/358423 which changed QPixmap(QString)
to take a path-like, breaking the implicit conversion from strings.

A workaround is to call addPixmap(QPixmap(str)).

Further classes where the constructors were modified to take a PathLike which could be relevant for implicit conversions: QDir, QFileInfo, QPixmap, QImage.
Ditto QFile, but that is not used for conversions.