v3.2.0

• cssnano no longer converts outline: none to outline: 0, as there are
  some cases where the values are not equivalent (thanks to @TrySound).
• cssnano no longer converts for example 16px to 1pc by default. Length
  optimisations can be turned on via {convertValues: {length: true}}.
• Improved minimization of css functions (thanks to @TrySound).