chore: bump github action "actions/checkout" 3 => 4 to fix deprecatio…

…ns (#1216)

Co-authored-by: Christopher Georg <christopher.georg@sr-travel.de>
Co-authored-by: Jonathan Beliën <jbelien@users.noreply.github.com>

.github/workflows/provider.yml

@@ -15,7 +15,7 @@ jobs:
       matrix:
         php-version: ['8.0', '8.1', '8.2']
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Use PHP ${{ matrix.php-version }}
       uses: shivammathur/setup-php@v2
       with: