Update demo.js version

Author: pnikolov

src/js/demo.js

@@ -1,4 +1,4 @@
-const demo = () => 'Webpack Boilerplate v5.17.1 - SASS/PostCSS, ES6/7, browser sync.';
+const demo = () => 'Webpack Boilerplate v5.18.0 - SASS/PostCSS, ES6/7, browser sync.';
 
 // eslint-disable-next-line no-console
 console.log(demo());