Update endpoints model

Author: AWS SDK for Go v2 automation user

codegen/smithy-aws-go-codegen/src/main/resources/software/amazon/smithy/aws/go/codegen/endpoints.json

@@ -3781,6 +3781,7 @@
           "ap-south-2" : { },
           "ap-southeast-1" : { },
           "ap-southeast-2" : { },
+          "ap-southeast-3" : { },
           "ap-southeast-4" : { },
           "bedrock-ap-northeast-1" : {
             "credentialScope" : {