message: Add `npm cache clean --force` hint for JSON issues
  [ci skip]
diff: Visual C++ Build Tools etc.)
  - If `npm install` fails on Ubuntu (e.g. while installing PhantomJS) you
  might have to install a recent version of Node.js and try again.
  +- If `npm install` runs into a `Unexpected end of JSON input` error you might need to clean your NPM cache with `npm cache clean --force` and then try again
  ## Docker
  