Bump actions/checkout from 5 to 6

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] <[email protected]>

Author: dependabot[bot]

.github/workflows/publish.yml

@@ -17,7 +17,7 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v6
         with:
           node-version: 24

.github/workflows/tests.yml

@@ -11,7 +11,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v6
         with:
           node-version: 22
@@ -37,7 +37,7 @@ jobs:
           https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md.
         run: echo 0 | sudo tee /proc/sys/kernel/apparmor_restrict_unprivileged_userns
         if: runner.os == 'Linux'
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}