cmake: link with target to also get include directory

cxx-generate-packed-data needs to link with protobuf library for the C++
source file.

Use the protobuf::libprotobuf to get both library and include directory.
Signed-off-by: Clément Péron <peron.clem@gmail.com>

build-cmake/CMakeLists.txt

@@ -220,7 +220,7 @@ GENERATE_TEST_SOURCES(${TEST_DIR}/test-full.proto t/test-full.pb-c.c t/test-full
 
 ADD_EXECUTABLE(cxx-generate-packed-data ${TEST_DIR}/generated-code2/cxx-generate-packed-data.cc t/test-full.pb.h t/test-full.pb.cc protobuf-c/protobuf-c.pb.cc protobuf-c/protobuf-c.pb.h)
 TARGET_LINK_LIBRARIES(cxx-generate-packed-data
-    ${PROTOBUF_LIBRARY}
+    protobuf::libprotobuf
     ${protobuf_ABSL_USED_TARGETS}
     ${protobuf_UTF8_USED_TARGETS}
 )