fix ci (#17)

.github/workflows/ci.yaml

@@ -1,22 +1,22 @@
 name: Unit Tests
 
-# TODO: reenable when https://github.com/swift-actions/setup-swift/issues/683 is resolved.
-# on:
-#   push:
-#     branches: [ main ]
-#   pull_request:
-#     branches: [ main ]
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
 
 jobs:
   build:
     name: Swift ${{ matrix.swift }} on ${{ matrix.os }}
     strategy:
       matrix:
-        os: [ubuntu-latest, macos-13]
+        os: [ubuntu-latest, macos-15]
         swift: ["6.0"]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: swift-actions/setup-swift@v2
+      - name: Setup Swift
+        uses: SwiftyLab/setup-swift@latest
         with:
           swift-version: ${{ matrix.swift }}
       - uses: actions/checkout@v4