chore: update alert & notification channel codeowners (#521)

Author: dbonf

CODEOWNERS

@@ -5,10 +5,11 @@
 *benchmark* @haresh-suresh  @nkraemer-sysdig
 
 # monitor
-*monitor*alert* @arturodilecce @dbonf
+*monitor*alert* @michelevergnano @dkutsanov @antonio-cuomo @dbonf
 *monitor*dashboard* @rossifrancesco
 *monitor*providers* @jwsarna1
 *monitor*groupmapping* @shadow649
+*notification_channel* @michelevergnano @dkutsanov @antonio-cuomo @dbonf
 
 # policies/rules
 *secure*policy* @kmvachhani @rosenbloomb-sysdig @ombellare @miguelgordo @ivanlysiuk-sysdig @daniel-almeida @jbainbridgesysdig @IvanNik @hila1608 @yaminSapir @chen-shmilovich-sysdig @zohar-arad