Fix iOS workflow still targeting old Xcode version

.github/workflows/ci.yml

@@ -121,21 +121,12 @@ jobs:
 
   build-only-ios:
     name: Build only (iOS)
-    # change to macos-latest once GitHub finishes migrating all repositories to macOS 12.
-    runs-on: macos-12
+    runs-on: macos-latest
     timeout-minutes: 60
     steps:
       - name: Checkout
         uses: actions/checkout@v2
 
-      # see https://github.com/actions/runner-images/issues/6771#issuecomment-1354713617
-      # remove once all workflow VMs use Xcode 14.1
-      - name: Set Xcode Version
-        shell: bash
-        run: |
-          sudo xcode-select -s "/Applications/Xcode_14.1.app"
-          echo "MD_APPLE_SDK_ROOT=/Applications/Xcode_14.1.app" >> $GITHUB_ENV
-
       - name: Install .NET 6.0.x
         uses: actions/setup-dotnet@v1
         with: