Fix Server Usage Sample to use ConnectedPeerCount

Author: Ubiguchi

README.md

@@ -89,7 +89,7 @@ server.Start(9050 /* port */);
 
 listener.ConnectionRequestEvent += request =>
 {
-    if(server.PeersCount < 10 /* max connections */)
+    if(server.ConnectedPeersCount < 10 /* max connections */)
         request.AcceptIfKey("SomeConnectionKey");
     else
         request.Reject();