Defer unwrapping config until actually evaluating the config() function

src/lib/evaluateTailwindFunctions.js

@@ -2,11 +2,10 @@ import _ from 'lodash'
 import functions from 'postcss-functions'
 
 export default function(config) {
-  const options = config()
-
   return functions({
     functions: {
       config: (path, defaultValue) => {
+        const options = config()
         return _.get(options, _.trim(path, `'"`), defaultValue)
       },
     },