Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/build-deploy.yml

@@ -17,7 +17,7 @@ jobs:
     name: Build Antora Site 🏗️
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Build Antora Site
         id: build_site
@@ -62,7 +62,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: build
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install OpenShift CLI tools
         uses: redhat-actions/openshift-tools-installer@v1