chore: [release-3.1.x] feat: Update doc-validator version (#13796)

Co-authored-by: Jack Baldry <[email protected]>

Author: grafanabot

.github/workflows/doc-validator.yml

@@ -7,7 +7,7 @@ jobs:
   doc-validator:
     runs-on: "ubuntu-latest"
     container:
-      image: "grafana/doc-validator:v5.0.0"
+      image: "grafana/doc-validator:v5.1.0"
     steps:
       - name: "Checkout code"
         uses: "actions/checkout@v4"