Find solution to matching Pybind11 versions between requirements.txt and GetPybind11.cmake

[mhucka]

What is the task?

The version of Pybind11 that pybind_interface/GetPybind11.cmake gets is not pinned in any way to the version specified in requirements.txt. That's likely to be the source of an obscure failure in the future. We should find a way to make sure they are the same version.

(Optional) Do you have ideas or preferences for the approach?

No response

How urgent is this for you?

None