Update Swift workflow

Author: tinder-cfuller

.github/workflows/swift.yml

@@ -7,14 +7,16 @@ on:
     branches: [ main ]
 
 env:
-  DEVELOPER_DIR: /Applications/Xcode_12.5.1.app/Contents/Developer
+  DEVELOPER_DIR: /Applications/Xcode_15.0.app/Contents/Developer
 
 jobs:
-  build_and_test:
-    runs-on: macos-11
+  swift:
+    name: Swift
+    runs-on: macos-13
     steps:
-    - uses: actions/checkout@v2
+    - name: Checkout source
+      uses: actions/checkout@v3
     - name: Build
-      run: swift build -v
-    - name: Run tests
+      run: swift build -v -Xswiftc -warnings-as-errors
+    - name: Test
       run: swift test -v