Update help message in doc.

Author: rubenmromero

README.md

@@ -72,9 +72,9 @@ Finally, you can add the script to your project repository executing the followi
 
 Here you are the message you will get if you request help to the `git_matrix.sh` script:
 
- $ ./git_matrix.sh -h
+ $ ./bin/git_matrix.sh --help
 
- EXECUTION MODE =>	./git_matrix.sh [-h|--help] [-k|--keep]
+ EXECUTION MODE =>	./bin/git_matrix.sh [-h|--help] [-k|--keep]
 
  Options:
  -h, --help	Show this help message and exit