Update CI to Xcode 15

Author: SplittyDev

.github/workflows/swift.yml

@@ -8,15 +8,16 @@ on:
 
 jobs:
   build:
+    runs-on: macos-13
     strategy:
-          matrix:
-            swift: ["5.5"]
+      matrix:
+        swift: ["5.5"]
     runs-on: macos-latest
     steps:
-    - uses: fwal/setup-swift@v1.11.0
+    - uses: maxim-lobanov/setup-xcode@v1
       with:
-          swift-version: ${{ matrix.swift }}
-    - uses: actions/checkout@v2
+        xcode-version: 15
+    - uses: actions/checkout@v3
     - name: Build
       run: swift build -v
     - name: Run tests