maintainers.md: Add Ilias, remove Pablo and Patrick

Update the list of maintainers.

Signed-off-by: Ilias Stamatis <ilstam@amazon.com>

Author: ilstam

MAINTAINERS.md

@@ -4,10 +4,9 @@ Firecracker is maintained by a dedicated team within Amazon:
 
 - Babis Chalios <bchalios@amazon.com>
 - Egor Lazarchuk <yegorlz@amazon.co.uk>
+- Ilias Stamatis <ilstam@amazon.com>
 - Jack Thomson <jackabt@amazon.com>
 - Marco Cali <xmarcalx@amazon.com>
 - Nikita Kalyazin <kalyazin@amazon.com>
-- Pablo Barbachano <pablob@amazon.com>
-- Patrick Roy <roypat@amazon.com>
 - Riccardo Mancini <mancio@amazon.com>
 - Takahiro Itazuri <itazur@amazon.com>