chore(ci): adding missing region in matrix (aws-powertools#5777)

Adding missing region in matrix

Author: leandrodamascena

.github/workflows/reusable_deploy_v3_layer_stack.yml

@@ -74,7 +74,7 @@ jobs:
         # aws ec2 describe-regions --all-regions --query "Regions[].RegionName" --output text | tr "\t" "\n" | sort
         region: ["af-south-1", "ap-east-1", "ap-northeast-1", "ap-northeast-2", "ap-northeast-3",
                  "ap-south-1", "ap-south-2", "ap-southeast-1", "ap-southeast-2", "ap-southeast-3",
-                 "ap-southeast-4", "ca-central-1", "ca-west-1", "eu-central-1", "eu-central-2",
+                 "ap-southeast-4", "ap-southeast-5", "ca-central-1", "ca-west-1", "eu-central-1", "eu-central-2",
                  "eu-north-1", "eu-south-1", "eu-south-2", "eu-west-1", "eu-west-2", "eu-west-3",
                  "il-central-1", "me-central-1", "me-south-1", "sa-east-1", "us-east-1",
                  "us-east-2", "us-west-1", "us-west-2"]