Add support for parsing proto map fields (#7613)

* Add support for proto 3 map to fbs gen

* Run clang-format

* Update proto golden test

* Rename variables

* Remove iostream

* Remove iostream

* Run clang format

Co-authored-by: Derek Bailey <derekbailey@google.com>

tests/proto_test.cpp

@@ -201,4 +201,4 @@ void ParseProtoBufAsciiTest() {
 }
 
 }  // namespace tests
-}  // namespace flatbuffers
+}  // namespace flatbuffers