Gulp-Workshop-Exercises

Hope this fix saves people some headaches. Gulp 4 has broken the gulpfile.js this Change will Update gulpfile.js to work with Gulp 4. for more info on the fix: https://stackoverflow.com/questions/36897877/gulp-error-the-following-tasks-did-not-complete-did-you-forget-to-signal-async https://stackoverflow.com/questions/39665773/gulp-error-watch-task-has-to-be-a-function