Add VS Code plugin to readme

Closes #608.

README.md

@@ -30,6 +30,7 @@ To get this up and running, install it using pip: `pip install proselint`.
 - [x] [Vim](https://github.com/amperser/proselint/tree/master/plugins/vim) (thanks to [Matthias Bussonnier](https://github.com/Carreau))
 - [x] [Phabricator's `arc` CLI](https://github.com/google/arc-proselint) (thanks to [Jeff Verkoeyen](https://github.com/jverkoey))
 - [x] [Danger](https://github.com/dbgrandi/danger-prose) (thanks to [David Grandinetti](https://github.com/dbgrandi) and [Orta Therox](https://github.com/orta)) 
+- [x] [Visual Studio Code](https://github.com/ppeszko/vscode-proselint) (thanks to [Patryk Peszko](https://github.com/ppeszko)) 
 
 ### Usage