Update date of scala symposium 2020

Author: Philippus

_events/2020-11-13-scala-symposium.md renamed to _events/2020-11-18-scala-symposium.md

@@ -4,7 +4,7 @@ title: Scala Symposium
 logo: /resources/img/scala-symposium.png
 location: Virtual
 description: "A scientific forum for researchers and practitioners focused on the Scala language."
-start: 13 November 2020
-end: 13 November 2020
+start: 18 November 2020
+end: 18 November 2020
 link-out: https://2020.ecoop.org/home/scala-2020
 ---