API version numbers will clash when writing bindings for an app or lib depending on other libraries

As unearthed by of https://codereview.qt-project.org/#/c/240451/ :

When writing bindings for a scriptable application using Qt, the default version number of the app (1.0) will trickle down to the typesystem imports and then, only unversioned Qt API will be parsed (fex, types since 5.12 will not be parsed).