Update tests.yml

Author: mattpolzin

.github/workflows/tests.yml

@@ -28,7 +28,7 @@ jobs:
     runs-on: macOS-latest
     steps:
       - name: Select latest available Xcode
-        uses: maxim-lobanov/setup-xcode@1.0
+        uses: maxim-lobanov/setup-xcode@v1.2.1
         with: { 'xcode-version': 'latest' }
       - name: Checkout code
         uses: actions/checkout@v2