Update generate-screenshots.js

Author: photonstorm

tools/generate-screenshots.js

@@ -82,7 +82,7 @@ const saveCanvas = async (page, example) => {
 
 async function run() {
     const browser = await puppeteer.launch({
-        headless: false,
+        headless: true,
     });
 
     const [page] = await browser.pages();