Merge pull request #6872 from sbueringer/pr-fix-linkchecker

📖 Set linkchecker base branch to main

Author: k8s-ci-robot

.github/workflows/lint-docs-pr.yaml

@@ -20,3 +20,4 @@ jobs:
         use-quiet-mode: 'yes'
         config-file: .markdownlinkcheck.json
         check-modified-files-only: 'yes'
+        base-branch: main