Add Cyrill to maintainers list (#917)

Signed-off-by: Cyrill Leutwiler <bigcyrill@hotmail.com>

MAINTAINERS.md

@@ -3,5 +3,6 @@
 ### Active Maintainers
 | name              | Github    | Discord        |
 |-------------------|-----------|----------------|
-| Sean Young        | seanyoung | seanyoung#0481 |
-| Lucas Steuernagel | LucasSte  | LucasSte#2331  |
+| Sean Young        | [@seanyoung](https://github.com/seanyoung) | seanyoung#0481 |
+| Lucas Steuernagel | [@LucasSte](https://github.com/LucasSte)  | LucasSte#2331  |
+| Cyrill Leutwiler  | [@xermicus](https://github.com/xermicus)  | kägifret#8095  |