• cssnano will no longer console.warn any messages when using deprecated
  options; these are now sent to PostCSS. You will be able to see them if you
  use a PostCSS runner with built-in messages support, or alternately by
  loading postcss-reporter or postcss-browser-reporter in your plugins list.
• Prepares support for grid identifier reduction by adding it to the list
  of optimisations turned off when options.safe is set to true.
• Adds support for normalizing unicode-range descriptors. Values will
  be converted when the code matches 0 & f in the same place on both sides
  of the range. So, u+2000-2fff can be converted to u+2???, but
  u+2100-2fff will be left as it is.