Update README with pip installation

Author: kpinnipa

README.md

@@ -20,10 +20,14 @@ for the frontend extension.
 - JupyterLab >= 3.0
 
 ## Install
-
+Install using jupyter:
 ```bash
 jupyter labextension install jupyterlab-code-snippets
 ```
+Install using pip:
+```bash
+pip install jupyterlab-code-snippets
+```
 
 ## Troubleshoot