Upgrade python/pybind11 to v2.6.2 am: c1e4e8e441 am: bf74725cfe

Original change: https://android-review.googlesource.com/c/platform/external/python/pybind11/+/1561635

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ie6d59cc4b5d16d866772ae15822bedc37df6ca72