Merge pull request #936 from serenity-js/renovate/actions-checkout-6.x

chore(deps): update actions/checkout action to v6

Author: jan-molak

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
         node-version: [ 18.x, 20.x, 22.x ]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Use Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v4
         with: