simple fix for single byte overflow on stack. (#52)

* simple fix for single byte overflow on stack.

you are writing 3 bytes into a 2 byte array.

* Update id3v2.cpp

Author: ihsinme

src/id3v2.cpp

@@ -3041,10 +3041,11 @@ void APar_ID3FrameAmmend(AtomicInfo *id32_atom,
     } else if (targetFrame->ID3v2_Frame_ID == ID3v2_FRAME_CONTENTTYPE) {
       uint8_t genre_idx = ID3StringGenreToInt(frame_payload);
       if (genre_idx != 0xFF) {
-        char genre_str_idx[2];
+        char genre_str_idx[4];
         genre_str_idx[0] = 0;
         genre_str_idx[1] = 0;
-        genre_str_idx[1] = 0;
+        genre_str_idx[2] = 0;
+        genre_str_idx[3] = 0;
         sprintf(genre_str_idx, "%u", genre_idx);
         APar_FrameDataPut(
             targetFrame, genre_str_idx, adjunct_payloads, str_encoding);