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

Author: renovate[bot]

.github/workflows/publish.yml

@@ -9,7 +9,7 @@ jobs:
   deploy:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5
+      - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6
         with:
           submodules: true  # Fetch Hugo themes (true OR recursive)
           fetch-depth: 0    # Fetch all history for .GitInfo and .Lastmod