ci: fix tests by using correct iOS version (#431)

Author: russellwheatley

.github/workflows/test.yaml

@@ -52,7 +52,7 @@ jobs:
           FIREBASE_TOKEN: ${{ env.FIREBASE_TOKEN }}
 
   test_macos:
-    runs-on: macos-latest
+    runs-on: macos-15
     timeout-minutes: 25
     environment: CI Environment
     env:
@@ -88,7 +88,7 @@ jobs:
           sudo npm i -g firebase-tools
       - name: Select Xcode version
         run: |
-          sudo xcode-select -switch /Applications/Xcode_16.2.app/Contents/Developer
+          sudo xcode-select -switch /Applications/Xcode_16.4.app/Contents/Developer
       - name: Install FlutterFire
         run: |
           dart pub global activate --source="path" . --executable="flutterfire" --overwrite        

packages/flutterfire_cli/test/configure_test.dart

@@ -533,7 +533,8 @@ void main() {
         fail(result2.stderr as String);
       }
 
-      const iosVersion = '13.0';
+      // Current Firebase iOS packages used by this test require iOS 15.0+.
+      const iosVersion = '15.0';
       // Update project.pbxproj
       final pbxprojResult = Process.runSync(
         'sed',
@@ -1572,7 +1573,8 @@ void main() {
         reason: 'Required FlutterFire scripts not found in project.pbxproj',
       );
 
-      const iosVersion = '13.0';
+      // Current Firebase iOS packages used by this test require iOS 15.0+.
+      const iosVersion = '15.0';
       // Update project.pbxproj
       final pbxprojResult = Process.runSync(
         'sed',