chore(ci): add XCode 16

Author: nfrechette

.github/workflows/build_pull_request.yml

@@ -67,7 +67,7 @@ jobs:
     runs-on: macos-14
     strategy:
       matrix:
-        compiler: [xcode15]
+        compiler: [xcode15, xcode16]
     steps:
       - name: Git checkout
         uses: actions/checkout@v4