[actions] Bump to Xcode 15.4 (#49)

Author: pjcollins

.github/workflows/build.yml

@@ -26,8 +26,8 @@ jobs:
           distribution: microsoft
           java-version: 17
 
-      - name: Use Xcode 15.3
-        run: sudo xcode-select -s /Applications/Xcode_15.3.app/Contents/Developer
+      - name: Use Xcode 15.4
+        run: sudo xcode-select -s /Applications/Xcode_15.4.app/Contents/Developer
 
       - name: Install MAUI
         run: dotnet workload install maui