Added NGINX Unit to the Servers list (#50)

* Added NGINX Unit to the Servers list

Added NGINX Unit (https://unit.nginx.org) to the list of servers supporting the ASGI specification.

* Update README.md

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Co-authored-by: Florimond Manca <[email protected]>

Author: Artem Konev

README.md

@@ -208,6 +208,7 @@ _Web servers for ASGI applications._
 
 - [Daphne](http://github.com/django/daphne) - An HTTP, HTTP2 and WebSocket protocol server for ASGI, developed to power Django Channels.
 - [Hypercorn](https://pgjones.gitlab.io/hypercorn/index.html) - An ASGI server based on the sans-io hyper, h11, h2, and wsproto libraries. Supports HTTP/1, HTTP/2, WebSockets, ASGI 2.0 and ASGI 3.0. Compatible with asyncio, uvloop and trio worker types.
+- [NGINX Unit](https://unit.nginx.org) - A universal web app server that supports ASGI.
 - [Uvicorn](https://www.uvicorn.org/) - A fast ASGI server based on uvloop and httptools. Supports HTTP/1 and WebSockets.
 
 ## Testing