fix year for Scala World 2017

Author: SethTisue

events/_posts/2017-09-18-scalaworld.md

@@ -4,7 +4,7 @@ title: Scala World
 logo: /resources/img/scala-world.png
 location: Lake District, UK
 description: Advanced Scala, hiking, biking and boating in beautiful scenery
-start: 16 September 2016
-end: 19 September 2016
+start: 16 September 2017
+end: 19 September 2017
 link-out: https://scala.world/
 ---