Updated dependencies

Author: robneu

package.json

@@ -22,7 +22,7 @@
     "grunt-contrib-copy": "1.x",
     "grunt-contrib-cssmin": "1.x",
     "grunt-contrib-imagemin": "1.x",
-    "grunt-contrib-uglify": "1.x",
+    "grunt-contrib-uglify": "2.x",
     "grunt-contrib-watch": "1.x",
     "grunt-jsbeautifier": "0.x",
     "grunt-newer": "1.x",
@@ -31,7 +31,7 @@
     "grunt-replace": "1.x",
     "grunt-rtlcss": "2.x",
     "grunt-sass": "1.x",
-    "grunt-shell": "1.x",
+    "grunt-shell": "2.x",
     "grunt-version": "1.x",
     "grunt-wp-i18n": "0.x",
     "time-grunt": "1.x"