Update actions/checkout digest to b4ffde6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
     timeout-minutes: 10
     steps:
       - name: Checkout code
-        uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4
 
       - name: Setup PHP
         uses: shivammathur/[email protected]