Merge pull request #23453 from bdach/appease-the-ios-monstrosity

Fix iOS build workflow failing

.github/workflows/ci.yml

@@ -121,12 +121,24 @@ jobs:
 
   build-only-ios:
     name: Build only (iOS)
-    runs-on: macos-latest
+    # `macos-13` is required, because Xcode 14.3 is required (see below).
+    # TODO: can be changed to `macos-latest` once `macos-13` becomes latest (currently in beta)
+    runs-on: macos-13
     timeout-minutes: 60
     steps:
       - name: Checkout
         uses: actions/checkout@v3
 
+      # newest Microsoft.iOS.Sdk versions require Xcode 14.3.
+      # 14.3 is currently not the default Xcode version (https://github.com/actions/runner-images/blob/main/images/macos/macos-13-Readme.md#xcode),
+      # so set it manually.
+      # TODO: remove when 14.3 becomes the default Xcode version.
+      - name: Set Xcode version
+        shell: bash
+        run: |
+          sudo xcode-select -s "/Applications/Xcode_14.3.app"
+          echo "MD_APPLE_SDK_ROOT=/Applications/Xcode_14.3.app" >> $GITHUB_ENV
+
       - name: Install .NET 6.0.x
         uses: actions/setup-dotnet@v3
         with: