Update pull request workflow to use the tagged github-workflows

Now that workflows is a more stable, use the most recent tag instead of
main to avoid changes to default jobs preventing merging.

Author: bnbarham

.github/workflows/pull_request.yml

@@ -17,12 +17,12 @@ concurrency:
 jobs:
   tests:
     name: Test
-    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
+    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@0.0.2
     with:
       enable_cross_pr_testing: true
   soundness:
     name: Soundness
-    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
+    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@0.0.2
     with:
       license_header_check_project_name: "Swift.org"
       api_breakage_check_allowlist_path: "api-breakages.txt"