Revert "test against 16.1"

This reverts commit 5701103.

Author: dplewis

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ on:
 env:
   CI_XCODE_14: /Applications/Xcode_14.2.app/Contents/Developer
   CI_XCODE_15: /Applications/Xcode_15.4.0.app/Contents/Developer
-  CI_XCODE_16: /Applications/Xcode_16.1.app/Contents/Developer
+  CI_XCODE_16: /Applications/Xcode_16.0.app/Contents/Developer
 jobs:
   tests:
     env: