updated version number in usage

src/ROCKparams.cpp

@@ -50,7 +50,7 @@ int ROCKparams::getfilterPEMode() {
 }*/
 
 void usage(int status) {
-cout<<"ROCK v@@@                    Copyright (C) 2016-2021 Institut Pasteur"<<endl;
+cout<<"ROCK 1.9.3                    Copyright (C) 2016-2021 Institut Pasteur"<<endl;
 cout<<endl;
 cout<<"Reducing Over-Covering K-mers within FASTQ file(s)"<<endl;
 cout<<endl;