bump grunt-html to ~3.0.0

Gruntfile.js

@@ -330,7 +330,6 @@ module.exports = function (grunt) {
         ignore: [
           'Attribute "autocomplete" not allowed on element "button" at this point.',
           'Attribute "autocomplete" not allowed on element "input" at this point.',
-          'Bad value "X-UA-Compatible" for attribute "http-equiv" on element "meta".',
           'Element "img" is missing required attribute "src".'
         ]
       },

package.json

@@ -51,7 +51,7 @@
     "grunt-contrib-watch": "~0.6.1",
     "grunt-csscomb": "~3.0.0",
     "grunt-exec": "~0.4.6",
-    "grunt-html": "~2.0.0",
+    "grunt-html": "~3.0.0",
     "grunt-jekyll": "~0.4.2",
     "grunt-jscs": "~1.5.0",
     "grunt-saucelabs": "~8.5.0",