don't use -u in install instructions

dominikh · dominikh · commit 805c59da7adf · 2015-02-01T08:36:15.000+01:00
diff --git a/README.md b/README.md
@@ -9,7 +9,7 @@ cases.
 ## Install
 
 ```sh
-go get -u honnef.co/go/netstat-nat
+go get honnef.co/go/netstat-nat
 ```
 
 ## Usage
