bump dev deps

Author: sindresorhus

package.json

@@ -38,10 +38,10 @@
   },
   "devDependencies": {
     "babel-preset-es2015": "^6.0.11",
-    "grunt": "^0.4.5",
-    "grunt-cli": "^0.1.13",
-    "grunt-contrib-clean": "^0.7.0",
-    "grunt-contrib-nodeunit": "^0.4.1",
+    "grunt": "^1.0.1",
+    "grunt-cli": "^1.2.0",
+    "grunt-contrib-clean": "^1.0.0",
+    "grunt-contrib-nodeunit": "^1.0.0",
     "xo": "*"
   },
   "xo": {