cleanup for removal of grunt-update-json

Author: Lauren McCarthy

Gruntfile.js

@@ -422,7 +422,6 @@ module.exports = function(grunt) {
   grunt.loadNpmTasks('grunt-newer');
   grunt.loadNpmTasks('grunt-release-it');
   grunt.loadNpmTasks('grunt-saucelabs');
-  grunt.loadNpmTasks('grunt-update-json');
   grunt.loadNpmTasks('grunt-karma');
   grunt.loadNpmTasks('grunt-contrib-clean');