GHA: Build on Xcode 15 and 16

Will it work?

.github/workflows/swift.yml

@@ -5,15 +5,30 @@ on:
   pull_request:
 
 jobs:
-  nextstep:
+  xcode15:
     runs-on: macos-13
     steps:
       - name: Select latest available Xcode
-        uses: maxim-lobanov/setup-xcode@v1
+        uses: maxim-lobanov/setup-xcode@v1.5.1
         with:
           xcode-version: '15.2.0'
       - name: Checkout Repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
+      - name: Build Swift Debug Package
+        run: swift build -c debug
+      - name: Build Swift Release Package
+        run: swift build -c release
+      - name: Run Tests
+        run: swift test
+  xcode16:
+    runs-on: macos-latest
+    steps:
+      - name: Select latest available Xcode
+        uses: maxim-lobanov/[email protected]
+        with:
+          xcode-version: latest
+      - name: Checkout Repository
+        uses: actions/checkout@v4
       - name: Build Swift Debug Package
         run: swift build -c debug
       - name: Build Swift Release Package