Use cross-pr-testing from github-workflows

Author: ahoppen

.github/workflows/pull_request.yml

@@ -7,10 +7,12 @@ on:
 jobs:
   tests:
     name: Test
-    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
-  soundness:
-    name: Soundness
-    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
+    uses: ahoppen/github-workflows/.github/workflows/swift_package_test.yml@cross-pr-testing
     with:
-      license_header_check_enabled: false
-      license_header_check_project_name: "Swift.org"
+      enable_cross_pr_testing: true
+  # soundness:
+  #   name: Soundness
+  #   uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
+  #   with:
+  #     license_header_check_enabled: false
+  #     license_header_check_project_name: "Swift.org"