docs: fix npm badge
# File Browser Front-end
[![CircleCI](https://img.shields.io/circleci/project/github/filebrowser/frontend.svg?style=flat-square)](https://circleci.com/gh/filebrowser/frontend)
-[![npm](https://img.shields.io/npm/v/filebrowser-frontend.svg)]()
+[![npm](https://img.shields.io/npm/v/filebrowser-frontend.svg?style=flat-square)]()
[![standard-readme compliant](https://img.shields.io/badge/readme%20style-standard-brightgreen.svg?style=flat-square)](https://github.com/RichardLitt/standard-readme)
> This is an example file with default selections.
