Modules: remove athens.azurefd.net

It appears to have been decommissioned (no valid TLS cert).

Change-Id: I7f9af976ce60129061473ac2244c8c1ec98e5caa
Reviewed-on: https://go-review.googlesource.com/c/wiki/+/647636
Auto-Submit: Ian Lance Taylor <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Commit-Queue: Ian Lance Taylor <[email protected]>

Author: seankhliao

Modules.md

@@ -841,7 +841,6 @@ For example:
 * [goproxy.cn](https://goproxy.cn) - Open source project - Run by [Qiniu Cloud](https://www.qiniu.com) - The most trusted Go module proxy in China.
 * [goproxy.io](https://goproxy.io) - Open source project - Run by [China Golang Contributor Club](https://golangcn.org) - A global proxy for Go modules.
 * [Athens](https://github.com/gomods/athens) - Open source project - Self-hosted - A Go module datastore and proxy.
-* [athens.azurefd.net](https://athens.azurefd.net) - Open source project - A hosted module proxy running Athens.
 * [Goproxy](https://github.com/goproxy/goproxy) - Open source project - Self-hosted - A minimalist Go module proxy handler.
 * [THUMBAI](https://thumbai.app) - Open source project - Self-hosted - Go mod proxy server and Go vanity import path server.