fix: upgrade handlebars to address dependency vulnerability issue
fix: upgrade handlebars to address dependency vulnerability issue

- handlebars v1.3.x uses a vulnerable version of uglify-js
- issue link: https://github.com/wycats/handlebars.js/pull/1084

ted123/hapi-swagger,ted123/hapi-swagger,School-Improvement-Network/hapi-swagger,School-Improvement-Network/hapi-swagger,fakewaffle/hapi-swagger,fakewaffle/hapi-swagger