Add Windows ACME Simple (win-acme) to clients list (#134)

* Add win-acme to clients list

* Use its official name ("Windows ACME Simple")

* Remove version number from WACS

README.md

@@ -311,6 +311,7 @@ logformat = "text"
 - Posh-ACME: [https://github.com/rmbolger/Posh-ACME](https://github.com/rmbolger/Posh-ACME)
 - Sewer: [https://github.com/komuw/sewer](https://github.com/komuw/sewer)
 - Traefik: [https://github.com/containous/traefik](https://github.com/containous/traefik)
+- Windows ACME Simple (WACS): [https://github.com/PKISharp/win-acme](https://github.com/PKISharp/win-acme)
 
 ### Authentication hooks