Bump actions/checkout from 5 to 6 in the github-actions group (#234)

Bumps the github-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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
  dependency-group: github-actions
...

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/ci.yml

@@ -20,7 +20,7 @@ jobs:
   #        - 119:119
   #        - 563:563
   #  steps:
-  #    - uses: actions/checkout@v5
+  #    - uses: actions/checkout@v6
   #    - uses: actions/setup-python@v5
   #      with:
   #        python-version: 3.13
@@ -43,7 +43,7 @@ jobs:
           - 119:119
           - 563:563
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
         with:
           enable-cache: true
@@ -59,7 +59,7 @@ jobs:
         node-version: [18.19.0]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}

.github/workflows/sphinx.yml

@@ -25,7 +25,7 @@ jobs:
   build_docs:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: astral-sh/setup-uv@v7
         with:
           enable-cache: true