include x-amz-request-id in request id deser (#606)

Author: kuhe

smithy-typescript-codegen/src/main/java/software/amazon/smithy/typescript/codegen/integration/HttpProtocolGeneratorUtils.java

@@ -230,7 +230,8 @@ static void generateMetadataDeserializer(GenerationContext context, SymbolRefere
                 () -> {
                     writer.write("httpStatusCode: output.statusCode,");
                     writer.write("requestId: output.headers[\"x-amzn-requestid\"] ??"
-                        + " output.headers[\"x-amzn-request-id\"],");
+                        + " output.headers[\"x-amzn-request-id\"] ??"
+                        + " output.headers[\"x-amz-request-id\"],");
                     writer.write("extendedRequestId: output.headers[\"x-amz-id-2\"],");
                     writer.write("cfId: output.headers[\"x-amz-cf-id\"],");
                 });