Add Swift package registry (#22404)

This PR adds a [Swift](https://www.swift.org/) package registry.


![grafik](https://user-images.githubusercontent.com/1666336/211842523-07521cbd-8fb6-400f-820c-ee8048b05ae8.png)

templates/swagger/v1_json.tmpl

@@ -2120,6 +2120,7 @@
               "pub",
               "pypi",
               "rubygems",
+              "swift",
               "vagrant"
             ],
             "type": "string",