Update SDK's smithy-go dependency to v1.18.0

Author: AWS SDK for Go v2 automation user

modman.toml

@@ -1,7 +1,7 @@
 
 [dependencies]
   "github.com/aws/aws-sdk-go" = "v1.44.28"
-  "github.com/aws/smithy-go" = "v1.17.0"
+  "github.com/aws/smithy-go" = "v1.18.0"
   "github.com/google/go-cmp" = "v0.5.8"
   "github.com/jmespath/go-jmespath" = "v0.4.0"
   "golang.org/x/net" = "v0.19.0"