Can't find/import 'capsule'

[dejancrn]

I'm having an issue similar to https://github.com/sizmailov/pybind11-stubgen/issues/86

It seems that py::capsule is not recognized correctly.
`
cls.def_static("from_raw_interface", [](py::capsule rawInterface)
{
if (std::strcmp(rawInterface.name(), "raw_interface") != 0)
throw std::invalid_argument("Invalid capsule");

daq::IBaseObject* obj = rawInterface.get_pointer<daq::IBaseObject>();
return obj;

});
`