build(deps): bump actions/checkout from 5 to 6 (#14)

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/ci.yaml

@@ -12,7 +12,7 @@ jobs:
     timeout-minutes: 5
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: hashicorp/setup-copywrite@v1.1.3
       - name: verify copyright
         run: |
@@ -22,7 +22,7 @@ jobs:
     timeout-minutes: 5
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: extractions/setup-just@e33e0265a09d6d736e2ee1e0eb685ef1de4669ff
       - uses: actions/setup-go@v6
         with: