changed README.md file to describe work for swagger codegen v3

Author: HugoMario

README.md

@@ -22,10 +22,10 @@
 :rocket: ProductHunt: https://producthunt.com/posts/swagger-codegen :rocket:
 
 ## Overview
-This is the swagger codegen project, which allows generation of API client libraries (SDK generation), server stubs and documentation automatically given an [OpenAPI Spec](https://github.com/OAI/OpenAPI-Specification). Currently, the following languages/frameworks are supported:
+This is the swagger codegen project, which allows generation of API client libraries (SDK generation), server stubs and documentation automatically given an [OpenAPI Spec v2 and v3](https://github.com/OAI/OpenAPI-Specification). Currently, the following languages/frameworks are supported:
 
-- **API clients**: **ActionScript**, **Ada**, **Apex**, **Bash**, **C#** (.net 2.0, 3.5 or later), **C++** (cpprest, Qt5, Tizen), **Clojure**, **Dart**, **Elixir**, **Elm**, **Eiffel**, **Erlang**, **Go**, **Groovy**, **Haskell** (http-client, Servant), **Java** (Jersey1.x, Jersey2.x, OkHttp, Retrofit1.x, Retrofit2.x, Feign, RestTemplate, RESTEasy, Vertx, Google API Client Library for Java), **Kotlin**, **Lua**, **Node.js** (ES5, ES6, AngularJS with Google Closure Compiler annotations) **Objective-C**, **Perl**, **PHP**, **PowerShell**, **Python**, **R**, **Ruby**, **Rust** (rust, rust-server), **Scala** (akka, http4s, swagger-async-httpclient), **Swift** (2.x, 3.x, 4.x), **Typescript** (Angular1.x, Angular2.x, Fetch, jQuery, Node)
-- **Server stubs**: **C#** (ASP.NET Core, NancyFx), **C++** (Pistache, Restbed), **Erlang**, **Go**, **Haskell** (Servant), **Java** (MSF4J, Spring, Undertow, JAX-RS: CDI, CXF, Inflector, RestEasy, Play Framework, [PKMST](https://github.com/ProKarma-Inc/pkmst-getting-started-examples)), **PHP** (Lumen, Slim, Silex, [Symfony](https://symfony.com/), [Zend Expressive](https://github.com/zendframework/zend-expressive)), **Python** (Flask), **NodeJS**, **Ruby** (Sinatra, Rails5), **Rust** (rust-server), **Scala** ([Finch](https://github.com/finagle/finch), [Lagom](https://github.com/lagom/lagom), Scalatra)
+- **API clients**: **Java** (Jersey1.x, Jersey2.x, OkHttp, Retrofit1.x, Retrofit2.x, Feign, RestTemplate, RESTEasy, Vertx, Google API Client Library for Java)
+- **Server stubs**: **Java** (Inflector)
 - **API documentation generators**: **HTML**, **Confluence Wiki**
 - **Configuration files**: [**Apache2**](https://httpd.apache.org/)
 - **Others**: **JMeter**
@@ -91,15 +91,15 @@ Swagger Codegen Version    | Release Date | OpenAPI Spec compatibility | Notes
 
 
 ### Prerequisites
-If you're looking for the latest stable version, you can grab it directly from Maven.org (Java 7 runtime at a minimum):
+Right now there is a release candidate (rc0) version, which you can grab it directly from Maven.org (Java 8 runtime at a minimum):
 
 ```sh
-wget http://central.maven.org/maven2/io/swagger/swagger-codegen-cli/2.3.0/swagger-codegen-cli-2.3.0.jar -O swagger-codegen-cli.jar
+wget http://central.maven.org/maven2/io/swagger/swagger-codegen-cli/3.0.0-rc0/swagger-codegen-cli-3.0.0-rc0.jar -O swagger-codegen-cli.jar
 
 java -jar swagger-codegen-cli.jar help
 ```
 
-For Windows users, you will need to install [wget](http://gnuwin32.sourceforge.net/packages/wget.htm) or you can use Invoke-WebRequest in PowerShell (3.0+), e.g. `Invoke-WebRequest -OutFile swagger-codegen-cli.jar http://central.maven.org/maven2/io/swagger/swagger-codegen-cli/2.3.0/swagger-codegen-cli-2.3.0.jar`
+For Windows users, you will need to install [wget](http://gnuwin32.sourceforge.net/packages/wget.htm) or you can use Invoke-WebRequest in PowerShell (3.0+), e.g. `Invoke-WebRequest -OutFile swagger-codegen-cli.jar http://central.maven.org/maven2/io/swagger/swagger-codegen-cli/3.0.0-rc0/swagger-codegen-cli-3.0.0-rc0.jar`
 
 On a mac, it's even easier with `brew`:
 ```sh
@@ -733,7 +733,9 @@ Instead of using `swaggerUrl` with an URL to the OpenAPI/Swagger spec, one can i
 Guidelines for Contribution
 ---------------------------
 
-Please refer to this [page](https://github.com/swagger-api/swagger-codegen/blob/master/CONTRIBUTING.md)
+Please refer to this [page.](https://github.com/swagger-api/swagger-codegen/blob/master/CONTRIBUTING.md)
+Also for `swagger-codegen version 3` templates and classes for code generation are being migrated to[swagger-codegen-generators](https://github.com/swagger-api/swagger-codegen-generators)
+repo. In order to know this migration process you can refer this [page.](https://github.com/swagger-api/swagger-codegen/wiki/Swagger-Codegen-migration-(swagger-codegen-generators-repository))
 
 Companies/Projects using Swagger Codegen
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