[readme] add ILIAS to users

Author: klees

README.md

@@ -3979,6 +3979,7 @@ Other Style Guides
   - **How About We**: [howaboutwe/javascript](https://github.com/howaboutwe/javascript-style-guide)
   - **HubSpot**: [HubSpot/javascript](https://github.com/HubSpot/javascript)
   - **Hyper**: [hyperoslo/javascript-playbook](https://github.com/hyperoslo/javascript-playbook/blob/master/style.md)
+  - **ILIAS**: [ILIAS](https://github.com/ILIAS-eLearning/ILIAS)
   - **InterCity Group**: [intercitygroup/javascript-style-guide](https://github.com/intercitygroup/javascript-style-guide)
   - **Jam3**: [Jam3/Javascript-Code-Conventions](https://github.com/Jam3/Javascript-Code-Conventions)
   - **JSSolutions**: [JSSolutions/javascript](https://github.com/JSSolutions/javascript)