Set version to next dev cycle

plugin.xml

@@ -3,7 +3,7 @@
 <plugin xmlns="http://apache.org/cordova/ns/plugins/1.0"
         xmlns:android="http://schemas.android.com/apk/res/android"
         id="de.appplant.cordova.plugin.local-notifications"
-        version="0.6.0">
+        version="0.6.1dev">
 
     <name>LocalNotifications</name>