Compilation with Clang fails for pybind11 3.0.1

For pybind11 3.0.1 our macOS compilation fails due to

/Users/gitlab/builds/tango-controls/pytango/ext/convertors/type_casters.h:58:51: error: passing no argument for the '...' parameter of a variadic macro is a C++20 extension [-Werror,-Wc++20-extensions]
   58 | PYBIND11_DECLARE_HOLDER_TYPE(T, LeakingSmartPtr<T>)