set version to 1.2.0

@@ -1132,7 +1132,7 @@ void get_outinfo_file_name(char * input)
 int main(int argc, char * argv[])
 {
 	if (argc < 2) {
-		printf("   merge_av 1.1.0\n");
+		printf("   merge_av 1.2.0\n");
 		printf("   run ffmpeg to merge audio and video files according to the record info file,\nusage:");
 		printf("\n   %s record_info_filename [-p] [-k]", argv[0]);
 		printf("\n   -p :only print the command,don't run ffmpeg");