Update pull_request.yml to only build on Linux and Windows

Author: shahmishal

.github/workflows/pull_request.yml

@@ -7,11 +7,13 @@ on:
 jobs:
   tests:
     name: Test
-    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@macos-support
+    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       linux_os_versions: '["amazonlinux2", "noble", "jammy", "focal", "rhel-ubi9", "bookworm"]'
       linux_swift_versions: '["6.1", "nightly-main"]'
+      linux_build_command: 'swift build'
       windows_swift_versions: '["6.1", "nightly-main"]'
+      windows_build_command: 'swift build'
       enable_macos_checks: true
       macos_xcode_versions: '["16.3"]'