Add new Go client (experimental) generator (#3268)

* add new go experimental generator

* extends go client codegen

* add go samples and test

* comment out haskell client test

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientExperimentalCodegen.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.openapitools.codegen.languages;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class GoClientExperimentalCodegen extends GoClientCodegen {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(GoClientExperimentalCodegen.class);
+
+    public GoClientExperimentalCodegen() {
+        super();
+    }
+
+    /**
+     * Configures a friendly name for the generator.  This will be used by the generator
+     * to select the library with the -g flag.
+     *
+     * @return the friendly name for the generator
+     */
+    @Override
+    public String getName() {
+        return "go-experimental";
+    }
+
+    /**
+     * Returns human-friendly help for the generator.  Provide the consumer with help
+     * tips, parameters here
+     *
+     * @return A string value for the help message
+     */
+    @Override
+    public String getHelp() {
+        return "Generates a Go client library (experimental and may subject to breaking changes without further notice).";
+    }
+
+}