[CODEOWNERS] Add chamons to synapse (Azure#17238)

Author: chamons

.github/CODEOWNERS

@@ -562,7 +562,7 @@ sdk/trafficmanager/Microsoft.Azure.Management.TrafficManager/            @tmsupp
 /sdk/support/Microsoft.Azure.Management.Support/           @shahbj79 @mit2nil @aygoya @ganganarayanan
 
 # ServiceLabel: %Synapse %Service Attention
-/sdk/synapse/            @aim-for-better @idear1203
+/sdk/synapse/            @aim-for-better @idear1203 @chamons
 
 # PRLabel: %Tables
 /sdk/tables/                                    @christothes