Add test proto file

Author: AdrienVannson

tests/inputs/message_wrapping/message_wrapping.proto

@@ -0,0 +1,11 @@
+syntax = "proto3";
+
+import "google/protobuf/duration.proto";
+import "google/protobuf/wrappers.proto";
+
+package message_wrapping;
+
+message MapMessage {
+    map<string, google.protobuf.FloatValue> map1 = 1;
+    map<string, google.protobuf.Duration> map2 = 2;
+}