globally pin the pybind11 versions

[beckermr]

Issue:

Environment (conda list):

$ conda list

Details about conda and system ( conda info ):

$ conda info

We got a report from @bluescarni (see conda-forge/conda-forge-pinning-feedstock#849 (comment)) that different pybind11 versions generate python libraries which are not interoperable between one another.

Assuming this is, in fact, true, we plan to globally pin the version of pybind11 for all of conda-forge. See conda-forge/conda-forge-pinning-feedstock#849. This will ease the maintenance burden for users who want to use different packages together and don't want to run around updating pins in recipes.

cc @conda-forge/core @conda-forge/pybind11

[henryiii]

This should only change when the internal ABI string changes. The string last changed for 2.4, I believe. Also, keep in mind that many (most?) packages internally pin pybind11, by submodule (in git) and including the headers in the SDist.

[beckermr]

This should only change when the internal ABI string changes.

What are you referring to? The pin?