redactional: change email address to my masters one

docs/index.md

@@ -57,7 +57,7 @@ The guardian professor was Prof. Dr. Gero Lueckemeyer
 [:fontawesome-brands-xing:{: style="color: teal"}][lueck-Xing].
 He is the current maintainer for this project and the appropriate contact for questions, access request, etc.
 
-[9l5-hft-mail]: mailto:62wilu1bif@hft-stuttgart.de
+[9l5-hft-mail]: mailto:11wilu1mst@hft-stuttgart.de
 [9l5GH]: https://www.github.com/9Lukas5
 [9l5GL]: https://www.gitlab.com/9Lukas5
 [9l5Twitter]: https://twitter.com/9Lukas5