[pybind11] Don't install Python

[nickanthony-dgl]

Is your feature request related to a problem? Please describe.

The vcpkg package for pybind11 lists python3 as a dependency. Having the vcpkg python3 package installed causes some problems if you want to instead use a non-vcpkg Python installation. #42322

Proposed solution

The pybind11 vcpkg package shouldn't make any assumptions about how Python will be installed, so I don't think "python3" should be listed as a dependency in the vcpkg.json file.

Describe alternatives you've considered

No response

Additional context

No response

[Osyotr]

Nothing has changed since the last attempt to decouple pybind11 and python3.
#40784

[nickanthony-dgl]

Thanks. I had searched for related issues before but for some reason didn't find that one. I don't really understand why an empty overlay port is better than just making the python3 optional, but I will go ahead and try that approach.

[dg0yt]

The dependency enforces a defined installation order between python3 and pybind.
The overlay port is to choose a different python3 implementation than the one provided by vcpkg.
Both things together help to ensure a reproducable result.