Require swift>=6.0 in pull request workflow

Author: jrflat

.github/workflows/pull_request.yml

@@ -10,14 +10,9 @@ jobs:
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       linux_os_versions: '["jammy", "focal"]'
+      linux_exclude_swift_versions: '[{"swift_version": "5.9"}, {"swift_version": "5.10"}]'
+      windows_exclude_swift_versions: '[{"swift_version": "5.9"}, {"swift_version": "5.10"}]'
       enable_macos_checks: true
-      # FIXME: https://github.com/swiftlang/github-workflows/pull/140
-      # Xcode 16.0 and 16.1 are not actually available
-      macos_exclude_xcode_versions: |
-        [
-          {"xcode_version": "16.0"},
-          {"xcode_version": "16.1"},
-        ]
       swift_flags: "-Xbuild-tools-swiftc -DSYSTEM_CI"
       enable_linux_static_sdk_build: true
       enable_wasm_sdk_build: true
@@ -31,13 +26,6 @@ jobs:
       enable_windows_checks: false
       # Only build
       macos_build_command: "xcrun swift build --build-tests"
-      # FIXME: https://github.com/swiftlang/github-workflows/pull/140
-      # Xcode 16.0 and 16.1 are not actually available
-      macos_exclude_xcode_versions: |
-        [
-          {"xcode_version": "16.0"},
-          {"xcode_version": "16.1"},
-        ]
       # Enable availability to match ABI stable verion of system.
       swift_flags: "-Xbuild-tools-swiftc -DSYSTEM_CI -Xbuild-tools-swiftc -DSYSTEM_ABI_STABLE"