docs(readme): update Node.js version requirement

Hans Kristian Flaatten · Hans Kristian Flaatten · commit af1a46b350ce · 2016-01-08T17:01:06.000+01:00
diff --git a/README.md b/README.md
@@ -10,8 +10,7 @@ Node.JS-client for [Nasjonal Turbase](http://www.nasjonalturbase.no).
 
 ## Requirements
 
-* Node.JS >= v0.10
-* io.js >= v1.0.0
+* Node.JS >= v4.0.0
 
 ## Install
 
