Update GitHub Actions to latest versions

Author: loevgaard

.github/workflows/build.yaml

@@ -22,7 +22,7 @@ jobs:
 
         steps:
             -   name: "Checkout"
-                uses: "actions/checkout@v4"
+                uses: "actions/checkout@v6"
 
             -   name: "Setup PHP, with composer and extensions"
                 uses: "shivammathur/setup-php@v2"
@@ -31,7 +31,7 @@ jobs:
                     coverage: "none"
 
             -   name: "Install composer dependencies"
-                uses: "ramsey/composer-install@v3"
+                uses: "ramsey/composer-install@v4"
 
             -   name: "Validate composer"
                 run: "composer validate --strict"