[CI] Add support for GitHub Actions

Author: shahmishal

.github/workflows/pull_request.yml

@@ -0,0 +1,16 @@
+name: Pull request
+
+on:
+  pull_request:
+    types: [opened, reopened, synchronize]
+
+jobs:
+  tests:
+    name: Test
+    uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
+    with:
+      linux_exclude_swift_versions: '[{"swift_version": "5.9"}, {"swift_version": "5.10"}]'
+      windows_exclude_swift_versions: '[{"swift_version": "5.9"}, {"swift_version": "5.10"}]'
+  soundness:
+    name: Soundness
+    uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main