Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/gh-pages-build-deploy.yml

@@ -37,7 +37,7 @@ jobs:
          rm pandoc-2.13-1-amd64.deb
 
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: build
         run: |
@@ -91,7 +91,7 @@ jobs:
     needs: build
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: sww1235/sww1235.github.io
           ref: main

.github/workflows/lint.yml

@@ -21,7 +21,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: markdownlint-cli
         # You may pin to the exact commit or the version.
@@ -41,14 +41,14 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: shellcheck
         uses: ludeeus/action-shellcheck@master
 
   css-lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: stylelint
         uses: sww1235/stylelint_gh_action@master
         env: