Build ios testflight app using xcode 15

Author: luckyrat

.github/workflows/flutter_build.yml

@@ -74,6 +74,7 @@ jobs:
     name: Build ios prod
 
     runs-on: macos-13
+    permissions: write-all
 
     steps:
       - name: Checkout

.github/workflows/flutter_release_ios.yml

@@ -119,6 +119,11 @@ jobs:
       - name: Run tests
         run: flutter test
 
+      - name: Choose xcode version
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: '15.0'
+
       - name: Build iOS Flutter App
         run: flutter build ios --config-only --release --no-codesign --dart-define KEEVAULT_STAGE=prod --dart-define KEEVAULT_NAME_SUFFIX= --dart-define KEEVAULT_ID_SUFFIX= --dart-define IAP_APPLE_APP_STORE=yes