Bump actions/checkout from 3 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/deploy.yml

@@ -10,7 +10,7 @@ jobs:
     name: Deploy docs
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: actions/[email protected]
         with:
           python-version: 3.x

.github/workflows/lint.yml

@@ -6,15 +6,15 @@ jobs:
   editorconfig-checker:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: editorconfig-checker
         run: |
           docker run --rm -v ${GITHUB_WORKSPACE}:/check mstruebing/editorconfig-checker
 
   yamllint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - name: yamllint
         run: |
           find ~+ ${github_workspace} -name '*.yaml' -o -name '*.yml' | xargs docker run --rm -v ${GITHUB_WORKSPACE}:${GITHUB_WORKSPACE} peterdavehello/yamllint yamllint -d '{extends: default, rules: {document-start: {present: false}, line-length: disable}}'