MAINTAINERS: make tagunil an ARC collaborator

Add myself to the ARC collaborators list, as I'm currently employed
by Synopsys to work on improving ARC support in Zephyr.

Signed-off-by: Ilya Tagunov <[email protected]>

Author: tagunil

MAINTAINERS.yml

@@ -133,6 +133,7 @@ ARC arch:
     - evgeniy-paltsev
   collaborators:
     - abrodkin
+    - tagunil
   files:
     - arch/arc/
     - include/zephyr/arch/arc/