Update Readme to indicate Swift 5 support

It appears that #9731 is merged and adds Swift 5 (5.x?) support which it would be nice to call out in the Readme, if accurate.

May want to add @plam4u (https://github.com/plam4u) to the Template Creator list, but I didn't want to do that without checking with them.

Author: haikusw

README.md

@@ -78,7 +78,7 @@ dependency example:
 ## 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:
 
-- **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, Rest-assured), **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)
+- **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, Rest-assured), **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, 5.x), **Typescript** (Angular1.x, Angular2.x, Fetch, jQuery, Node)
 - **Server stubs**: **Ada**, **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)), **Kotlin**, **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 documentation generators**: **HTML**, **Confluence Wiki**
 - **Configuration files**: [**Apache2**](https://httpd.apache.org/)