+ koa logger update

package.json

@@ -30,7 +30,7 @@
     "koa-convert": "^1.2.0",
     "koa-etag": "^2.0.0",
     "koa-helmet": "^1.0.0",
-    "koa-logger": "^1.2.2",
+    "koa-logger": "^2.0.0",
     "koa-prerender": "^1.0.3",
     "koa-route": "^3.1.0",
     "koa-static": "^2.0.0",

src/server.js

@@ -30,7 +30,7 @@ export default function(){
             json: 'application/ejson'
         }
     }));
-    app.use($(logger()));
+    app.use(logger());
     app.use(api());
     app.use($(conditional()));
     app.use($(etag()));