BUG: can't find QRegularExpressionValidator when running with pyside2

Description

When running tests with pyside2 (qt5), it raises an error:

AttributeError: module 'qtpy.QtGui' has no attribute 'QRegularExpressionValidator'

It seems that pyside2 bindings for qtpy doesn't include QtGui.QRegularExpressionValidator, altough it seems that QRegularExpressionValidator is part of QtGui on pyside2 docs.

Still needs to investigate if qtpy really lacks this binding or this error happens for another reason.