Updated to latest-stable Xcode and macOS for GitHub Actions

Author: malcommac

.github/workflows/all.yml

@@ -18,14 +18,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        xcode: ["13.4.1"]
+        xcode: [latest-stable]
         include:
-          - xcode: "13.4.1"
-            macos: macOS-12
+          - xcode: latest-stable
+            macos: macos-latest
     runs-on: ${{ matrix.macos }}
     env:
       DEVELOPER_DIR: /Applications/Xcode_${{ matrix.xcode }}.app/Contents/Developer
     steps:
       - uses: actions/checkout@v2
       - name: Run Tests
-        run: swift test
+        run: swift test