6.0.0 - Swift 6 & Strict Concurrency

This is a major release after transitioning the repository to my personal account. I'll be the core maintainer of Diagnostics now 🎉
I went over the whole package and updated it for the future. This does mean that Xcode 26 is required to make use of the latest Swift functionalities. Yet, it does mean better performance, more stability, and strict concurrency enabled.

What's Changed

• Update changelog for 5.0.0 release by @raphkoebraam in #174
• Add visionOS support by @Rubenfer in #175
• Update Diagnostics to Swift 6 by @AvdLee in #182
• Clear contents for repository transfer to AvdLee by @AvdLee in #183
• Fix CI and add GitHub workflow for running tests on PRs by @AvdLee in #184

Full Changelog: 5.0.0...6.0.0