[GO][SERVER] Implement response code (#7397)

* Feature(template) add response with status code generation

* Generate Samples

* update samples

Co-authored-by: William Cheng <wing328hk@gmail.com>

samples/server/petstore/go-api-server/go/impl.go

@@ -0,0 +1,16 @@
+/*
+ * OpenAPI Petstore
+ *
+ * This is a sample server Petstore server. For this sample, you can use the api key `special-key` to test the authorization filters.
+ *
+ * API version: 1.0.0
+ * Generated by: OpenAPI Generator (https://openapi-generator.tech)
+ */
+
+package petstoreserver
+
+//Implementation response defines an error code with the associated body
+type ImplResponse struct {
+	Code int
+	Body interface{}
+}