Pin Pybind Version (#418)

* aligning the pybind versions to v2.12 for core and python_backend

* Review comment

---------

Co-authored-by: Kyle McGill <kmcgill@nvidia.com>

Author: fpetrini15

python/tritonserver/CMakeLists.txt

@@ -43,8 +43,8 @@ include(FetchContent)
 FetchContent_Declare(
   pybind11
   GIT_REPOSITORY "https://github.com/pybind/pybind11"
-  # COMMIT ID for v2.10.0
-  GIT_TAG "aa304c9c7d725ffb9d10af08a3b34cb372307020"
+  # COMMIT ID for v2.12.0
+  GIT_TAG "3e9dfa2866941655c56877882565e7577de6fc7b"
   GIT_SHALLOW ON
 )
 FetchContent_MakeAvailable(pybind11)