ci: implement dual-version Swift testing (6.0 + 6.2)

- Add macOS jobs for Swift 6.0 (Xcode 16.0) and 6.2 (Xcode 16.2)
- Add Linux jobs for Swift 6.0 and 6.2 containers
- Test both debug and release configurations on macOS
- Ensures compatibility at both ends of support range (Point-Free approach)

Author: coenttb

.github/workflows/ci.yml

@@ -14,8 +14,8 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  macos:
-    name: macOS (Swift 6.0+)
+  macos-swift60:
+    name: macOS (Swift 6.0)
     runs-on: macos-15
     strategy:
       matrix:
@@ -44,15 +44,55 @@ jobs:
       - name: Run tests
         run: swift test -c ${{ matrix.config }}
 
-  linux:
+  macos-swift62:
+    name: macOS (Swift 6.2)
+    runs-on: macos-15
+    strategy:
+      matrix:
+        xcode: ['16.2']
+        config: ['debug', 'release']
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Select Xcode ${{ matrix.xcode }}
+        run: sudo xcode-select -s /Applications/Xcode_${{ matrix.xcode }}.app
+
+      - name: Print Swift version
+        run: swift --version
+
+      - name: Cache Swift packages
+        uses: actions/cache@v4
+        with:
+          path: .build
+          key: ${{ runner.os }}-spm-${{ hashFiles('Package.resolved') }}
+          restore-keys: |
+            ${{ runner.os }}-spm-
+
+      - name: Build
+        run: swift build -c ${{ matrix.config }}
+
+      - name: Run tests
+        run: swift test -c ${{ matrix.config }}
+
+  linux-swift60:
     name: Ubuntu (Swift 6.0)
     runs-on: ubuntu-latest
     container: swift:6.0
     steps:
       - uses: actions/checkout@v5
 
-      - name: Resolve dependencies
-        run: swift package resolve
+      - name: Build
+        run: swift build
+
+      - name: Run tests
+        run: swift test
+
+  linux-swift62:
+    name: Ubuntu (Swift 6.2)
+    runs-on: ubuntu-latest
+    container: swift:6.2
+    steps:
+      - uses: actions/checkout@v5
 
       - name: Build
         run: swift build