Folder name sample_scripts changed to samples

There is no folder anymore which is called `sample_scripts` however there is a folder called `samples` which has a `peptide.py` file.

README.md

@@ -130,7 +130,7 @@ that uses the virtual environment.
 
 ```sh
 source pymbe/bin/activate
-python3 sample_scripts/peptide.py
+python3 samples/peptide.py
 deactivate
 ```