Update dependencies

Author: hail2u

package.json

@@ -10,12 +10,12 @@
     "url": "https://github.com/hail2u/node-csswring/issues"
   },
   "dependencies": {
-    "minimist": "^1.1.0",
+    "minimist": "^1.2.0",
     "onecolor": "^3.0.4",
-    "postcss": "^5.0.0"
+    "postcss": "^6.0.0"
   },
   "devDependencies": {
-    "nodeunit": "^0.10.2"
+    "nodeunit": "^0.11.0"
   },
   "engines": {
     "node": ">=5.0.0"