Update example in Source Readme.

Author: uli-objectbox

Source/README.md

@@ -154,6 +154,6 @@ Then you're all set to use entities with ObjectBox:
 
  // Get collections of entities
  _ = personBox.all()
- _ = personBox.query({ Person.name == "Fry" }).find()
+ _ = personBox.query({ Person.name == "Fry" }).build().find()
 
 That's it, it works now!