message: fix link to package.json in MD file
diff: @@ -30,8 +30,8 @@ $ yarn docker-build
  $ docker run --rm -it -p 80:80 spotify/backstage
  ```
  -> See [package.json](package.json) for other yarn commands/options.
  -
  Then open http://localhost/ on your browser.
  +> See [package.json](/package.json) for other yarn commands/options.
  +
  [Back to Docs](README.md)
  