chore(deps): update actions/checkout action to v4.3.1

Author: renovate[bot]

.github/workflows/pull_request.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repo
-        uses: actions/checkout@v4.1.1
+        uses: actions/checkout@v4.3.1
         with:
           fetch-depth: 0 # important!
       - name: Cache Composer dependencies