Update postcss plugin docs?

[groovecoder]

The docs suggest I should use doiuse as a postcss plugin like this?

          postcss(doiuse({onFeatureUsage:function(usageInfo){
            alert(usageInfo.message);
          }})).process(styleSheetContent)

But, I had to use it this way:

          postcss([doiuse]).process(styleSheetContent).then(function(result) {
            alert(result);
          });

?

[ismay]

Haven't had time to test this, but you're right, that is in line with the postcss api docs: http://api.postcss.org/Processor.html. Would you be open to submit a pr to fix this in the readme?