[workflows] attempt 2D exclusions

Author: glessard

.github/workflows/pull_request.yml

@@ -10,6 +10,7 @@ jobs:
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       linux_os_versions: '["noble", "jammy", "focal"]'
+      linux_exclude_swift_versions: '[{"os_version": "focal", "swift_version": "nightly-main"}, {"os_version": "noble", "swift_version": "5.9"}]'
       enable_macos_checks: true
       # FIXME: https://github.com/swiftlang/github-workflows/pull/140
       # Xcode 16.0 and 16.1 are not actually available