Bump actions/checkout from 5 to 6 in the github-actions group

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>

Author: dependabot[bot]

.github/workflows/publish.yml

@@ -9,7 +9,7 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: extractions/setup-just@v3
       - uses: astral-sh/setup-uv@v7
         with:

.github/workflows/test.yml

@@ -15,7 +15,7 @@ jobs:
   check-types:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: extractions/setup-just@v3
       - uses: astral-sh/setup-uv@v7
         with:
@@ -25,7 +25,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: extractions/setup-just@v3
       - uses: astral-sh/setup-uv@v7
         with:
@@ -42,7 +42,7 @@ jobs:
           - "3.12"
           - "3.13"
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: extractions/setup-just@v3
       - uses: astral-sh/setup-uv@v7
         with: