fix(ios): Set minimum XCode version in GitHub Action to 15

- The iOS 16.x Test failed, because the XCode version 14.x could not be found. A minimum XCode version would be 15.x.
- Made ios-version 15.x test equal with with the other tests. There is no need to run an older xcode version on an older macos version. Event the recent XCode version 26 does support iOS 15, so it's ok to use minimum XCode 15.

Author: GitToTheHub

.github/workflows/ios.yml

@@ -50,13 +50,13 @@ jobs:
     strategy:
       matrix:
         versions:
-          - os-version: macos-12
+          - os-version: macos-14
             ios-version: 15.x
-            xcode-version: 13.x
+            xcode-version: 15.x
 
           - os-version: macos-14
             ios-version: 16.x
-            xcode-version: 14.x
+            xcode-version: 15.x
 
           - os-version: macos-14
             ios-version: 17.x