fix: Allow for loading local files when creating screenshots and wait for the page to load before taking screenshot.

Author: stevebritton

lib/gulp/screenshot.js

@@ -47,14 +47,14 @@ module.exports = function(gulp, options) {
         }
 
         const openBrowser = async () => {
-            const browser = await puppeteer.launch();
+            const browser = await puppeteer.launch({ args:['--allow-file-access-from-files'] });
             return browser;
         };
 
         const renderPage = async (browser, url, output) => {
             const page = await browser.newPage();
             await page.emulate(iPad);
-            await page.goto(url + '#screenshot');
+            await page.goto(url + '#screenshot', { waitUntil: 'networkidle0' });
             await page.screenshot({path: output + '.png'});
         };