fix: example project doesn't work

Author: pvasek

examples/react-styleguidist-example/README.md

@@ -1,7 +1,7 @@
 # Example project
 
-First you need to install depedencies either by running `yarn install` or `npm install`.
+First you need to install depedencies either by running `npm install`.
 
-Then you can start it with `yarn start` or `npm start` and navigate to http://localhost:6060/.
+Then you can start it with `npm start` and navigate to http://localhost:6060/.
 
 The project was tested against the _node version v10.0.1_.