broken link in src/libs/README.md

[Alexei Pastuchov]

The link "Zulip and how the Rust community uses it." on src/libs/README.md has the target https://github.com/rust-lang/rust-forge/blob/master/chat/zulip.html, which doesn't exists.

Same issue on https://forge.rust-lang.org/libs/index.html

[XAMPPRocky]

Thank you for your issue! Should be fixed now.