Bump action checkout

Author: hannesa2

.github/workflows/BuildPR.yml

@@ -18,7 +18,7 @@ jobs:
       - name: ls Xcode
         run: ls -la /Applications/Xcode*
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
           submodules: true