Bump actions/checkout from 5 to 6 (#9)

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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/docs.yaml

@@ -12,6 +12,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Build and push docs
         uses: athackst/mkdocs-simple-plugin@v3.2.4

.github/workflows/ros.yaml

@@ -16,7 +16,7 @@ jobs:
     steps:
       - 
         name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       -
         name: Test
         uses: ./.github/actions/test/
@@ -31,7 +31,7 @@ jobs:
     steps:
       - 
         name: Checkout code
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       -
         name: Run linter
         uses: ./.github/actions/lint/