Hand maintenance over to Mikel Stellio (!114)

## What is the new feature
Hand maintenance over to Mikel Stellio

Merged-by: Jonas Jucker <jonas.jucker@env.ethz.ch>
Changelog: other

AUTHORS.txt

@@ -12,6 +12,7 @@ Jonas Jucker
 Leonidas Linardakis
 Luis Kornblueh
 Marek Jacob
+Mikael Stellio
 Monika Esch
 Nathanael Huebbe
 Pradipta Samanta

README.md

@@ -106,7 +106,7 @@ Please open a merge request and select one of our templates: __[feature/bugfix]_
 ## Contact
 This repository is mainly maintained by the following maintainers:
 - __Yen-Chen Chen__ (yen-chen.chen@kit.edu)
-- __Jonas Jucker__ (jonas.jucker@env.ethz.ch)
+- __Mikael Stellio__ (mikael.stellio@c2sm.ethz.ch)
 - __Will Sawyer__ (william.sawyer@cscs.ch)
 
 This repository is owned by the `icon-libraries` group, contacts about general ICON library questions: