fix(swift-ci): use Xcode 16.1 for iOS 18.1 simulator support

Xcode 15.4 doesn't include iOS 18.1 simulators (only iOS 17.x).
Updated to Xcode 16.1 which includes iOS 18 simulators.

Author: shubhammalhotra28

.github/workflows/swift-sdk-release.yml

@@ -90,7 +90,7 @@ jobs:
       - name: Setup Xcode
         uses: maxim-lobanov/setup-xcode@v1
         with:
-          xcode-version: '15.4'
+          xcode-version: '16.1'
 
       - name: Install SwiftLint and xcpretty
         run: |