GHA: Try Xcode26 beta build

... will it work?

Author: helje5

.github/workflows/swift.yml

@@ -8,8 +8,8 @@ jobs:
   xcode15:
     runs-on: macos-13
     steps:
-      - name: Select latest available Xcode
-        uses: maxim-lobanov/setup-xcode@v1.5.1
+      - name: Select Xcode 15.2
+        uses: maxim-lobanov/setup-xcode@v1.6.0
         with:
           xcode-version: '15.2.0'
       - name: Checkout Repository
@@ -24,7 +24,7 @@ jobs:
     runs-on: macos-latest
     steps:
       - name: Select latest available Xcode
-        uses: maxim-lobanov/setup-xcode@v1.5.1
+        uses: maxim-lobanov/setup-xcode@v1.6.0
         with:
           xcode-version: latest
       - name: Checkout Repository
@@ -35,3 +35,18 @@ jobs:
         run: swift build -c release
       - name: Run Tests
         run: swift test
+  xcode26:
+    runs-on: macos-latest
+    steps:
+      - name: Select Xcode 26-beta
+        uses: maxim-lobanov/setup-xcode@v1.6.0
+        with:
+          xcode-version: 26-beta
+      - name: Checkout Repository
+        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