py-pybind11: updated to 2.10.3

Version 2.10.3

Changes:

Temporarily made our GIL status assertions (added in 2.10.2) disabled by default (re-enable manually by defining PYBIND11_ASSERT_GIL_HELD_INCREF_DECREF, will be enabled in 2.11).
Improved error messages when inc_ref/dec_ref are called with an invalid GIL state.

Bug Fixes:

Some minor touchups found by static analyzers.

(adam)