Add missing plot.py to README project structure

Author: tal123ph

README.md

@@ -57,6 +57,7 @@ Quantifying/
 │   ├── 1-fetch/
 │   ├── 2-process/
 │   ├── 3-report/
+    └── plot.py  # Data visualisations with matplotlib
 │   └── shared.py
 ├── .cc-metadata.yml
 ├── .flake8  # Python tool configuration