Log Xcode version after selection

Author: MaxDesiatov

.github/workflows/main.yml

@@ -127,6 +127,7 @@ jobs:
       - name: Build macOS installable archive
         run: |
           sudo xcode-select --switch /Applications/Xcode_12.2.app/Contents/Developer/
+          xcodebuild -version
           ./utils/webassembly/ci.sh
       - name: Upload macOS installable archive
         uses: actions/upload-artifact@v1