[codeofconduct] Add contact address for incident reports

CODE_OF_CONDUCT.md

@@ -60,7 +60,10 @@ representative at an online or offline event.
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
 reported to the community leaders responsible for enforcement at
-[INSERT CONTACT METHOD].
+* Bernd Flemisch: bernd at iws.uni-stuttgart.de
+* and/or Timo Koch: timokoch at uio.no
+* and/or Dennis Gläser: dennis.glaeser at iws.uni-stuttgart.de
+
 All complaints will be reviewed and investigated promptly and fairly.
 
 All community leaders are obligated to respect the privacy and security of the