Update package.json (#125)

Author: C-Lodder

package.json

@@ -43,7 +43,7 @@
     "grunt-contrib-copy": "latest",
     "grunt-contrib-cssmin": "latest",
     "grunt-contrib-uglify-es": "git://github.com/gruntjs/grunt-contrib-uglify.git#harmony",
-    "grunt-postcss-x": "latest",
+    "@lodder/grunt-postcss": "latest",
     "grunt-sass": "^3.0.2",
     "grunt-shell": "latest",
     "node-sass": "^4.12.0",