update rev proxy example

examples/h2o.conf

@@ -4,6 +4,6 @@ hosts:
   "*":
     paths:
       /:
-        proxy.reverse.url: "http://[unix:/home/hydro/hydro.sock]"
+        proxy.reverse.url: "http://localhost:8888"
         proxy.preserve-host: ON
         proxy.websocket: ON