We will discontinue support for Swift 5.8 on Linux in our GitHub Actions CI testing starting March 24th. Drop support for Swift 5.8 from Linux workflows by shahmishal · Pull Request #107 · swiftlang/github-workflows · GitHub
If you are using swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main in your GitHub Actions workflows and have the check Test / Linux (5.8 - jammy) enabled, you will need to remove it from your requirements.