refactor: rename packet_utils.cpp to packet.cpp

src/packet/CMakeLists.txt

@@ -1,9 +1,9 @@
 add_library(packet
+    packet.cpp
     packet_parser.cpp
     packet_builder.cpp
     packet_filter.cpp
     packet_dump.cpp
-    packet_utils.cpp
     packet_ldbc.cpp
     packet_layer.cpp
     packet_tunnel.cpp