Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/website.yml

@@ -16,21 +16,21 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout uutils.github.io Repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         repository: uutils/uutils.github.io
         path: './uutils.github.io'
         fetch-depth: 0
 
     - name: Checkout Coreutils Repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         repository: uutils/coreutils
         path: './coreutils'
         fetch-depth: 0
 
     - name: Checkout Findutils Repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         repository: uutils/findutils
         path: './findutils'