Download visionOS in CI (#38)

Author: dfed

.github/workflows/ci.yml

@@ -45,6 +45,9 @@ jobs:
         run: bundle install
       - name: Select Xcode Version
         run: sudo xcode-select --switch /Applications/Xcode_15.4.app/Contents/Developer
+      - name: Download visionOS
+        if: matrix.platforms == 'visionOS_1'
+        run: xcodebuild -downloadPlatform visionOS
       - name: Build and Test Framework
         run: Scripts/build.swift ${{ matrix.platforms }}
       - name: Prepare Coverage Reports