Contributing to Swift guide Link not working in README

[louisunlimited]

When clicking on Contributing to Swift guide:

swiftly/README.md

Line 64 in df0e91c

Contributions to Swiftly are welcomed and encouraged! Please see the [Contributing to Swift guide](swift.org/contributing) and check out the [structure of the community](https://www.swift.org/community/#community-structure).

the link get treated as a relative path to this repo instead of an external site, resulting in a 404 not found.
(taking us to https://github.com/swiftlang/swiftly/blob/main/swift.org/contributing)

swift.org/contributing is a working link, just referenced wrong

[cmcgee1024]

This should be fixed with pr #336