bug fix for passing in 'true' for isPreview not being respected

Author: jamesvidler

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@agility/content-fetch",
-  "version": "0.5.4",
+  "version": "0.5.5",
   "description": "JavaScript library for the Agility Fetch API (node and browser)",
   "main": "dist/agility-content-fetch.node.js",
   "scripts": {

src/utils.js

@@ -2,7 +2,7 @@ function buildRequestUrlPath(config, languageCode) {
     let urlPath = null;
     let apiFetchOrPreview = null;
 
-    if(config.isPreview) {
+    if(config.isPreview === true || config.isPreview === 'true') {
         apiFetchOrPreview  = 'preview';
     } else {
         apiFetchOrPreview = 'fetch';