TEST: rework pybind11_protobuf fix

* Try to get rid of ${Python_LIBRARIES} unavailable on manylinux
note: module shouldn't link against libpython but only depends on python.h
since it will be dynamic loaded in the python process.

patches/pybind11_protobuf.patch

@@ -1,8 +1,30 @@
 diff --git a/CMakeLists.txt b/CMakeLists.txt
-index e936f66..5461aaf 100644
+index e936f66..eaac571 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
-@@ -57,7 +57,7 @@ target_include_directories(
+@@ -21,7 +21,7 @@ option(BUILD_TESTS "Build tests." OFF)
+ # ============================================================================
+ # Find Python
+
+-find_package(Python COMPONENTS Interpreter Development)
++find_package(Python3 COMPONENTS Interpreter Development.Module)
+
+ # ============================================================================
+ # Build dependencies
+@@ -47,8 +47,10 @@ pybind11_add_module(
+   pybind11_protobuf/proto_utils.h)
+
+ target_link_libraries(
+-  pybind11_proto_utils PRIVATE absl::strings protobuf::libprotobuf
+-                               ${Python_LIBRARIES})
++  pybind11_proto_utils PRIVATE
++    absl::strings
++    protobuf::libprotobuf
++    Python3::Module)
+
+ target_include_directories(
+   pybind11_proto_utils PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS}
+@@ -57,7 +59,7 @@ target_include_directories(
  # ============================================================================
  # pybind11_native_proto_caster shared library
  add_library(
@@ -11,7 +33,12 @@ index e936f66..5461aaf 100644
    # bazel: pybind_library: native_proto_caster
    pybind11_protobuf/native_proto_caster.h
    # bazel: pybind_library: enum_type_caster
-@@ -83,6 +83,8 @@ target_link_libraries(
+@@ -79,10 +81,12 @@ target_link_libraries(
+   absl::optional
+   protobuf::libprotobuf
+   pybind11::pybind11
+-  ${Python_LIBRARIES})
++  Python3::Module)
 
  target_include_directories(
    pybind11_native_proto_caster
@@ -20,6 +47,15 @@ index e936f66..5461aaf 100644
    PRIVATE ${PROJECT_SOURCE_DIR} ${protobuf_INCLUDE_DIRS} ${protobuf_SOURCE_DIR}
            ${pybind11_INCLUDE_DIRS})
 
+@@ -109,7 +113,7 @@ target_link_libraries(
+   absl::optional
+   protobuf::libprotobuf
+   pybind11::pybind11
+-  ${Python_LIBRARIES})
++  Python3::Module)
+
+ target_include_directories(
+   pybind11_wrapped_proto_caster
 diff --git a/pybind11_protobuf/proto_cast_util.cc b/pybind11_protobuf/proto_cast_util.cc
 index 06bde44..1cc6a30 100644
 --- a/pybind11_protobuf/proto_cast_util.cc