Update actions/checkout to v4

Author: jakzal

.github/workflows/build.yml

@@ -58,7 +58,7 @@ jobs:
             matrix:
                 php: [8.1, 8.2, 8.3]
         steps:
-            -   uses: actions/checkout@v3
+            -   uses: actions/checkout@v4
 
             -   name: Setup PHP
                 uses: shivammathur/setup-php@v2