Bump actions/checkout from 5 to 6 (#18)

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

Author: dependabot[bot]

.github/workflows/publish.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Determine versions
         id: versions
         run: |

.github/workflows/test.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Brioche
         uses: ./ # Uses an action in the root directory
@@ -52,7 +52,7 @@ jobs:
     runs-on: ${{ matrix.runs-on }}
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Brioche
         uses: ./ # Uses an action in the root directory
@@ -65,7 +65,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Brioche
         uses: ./ # Uses an action in the root directory
@@ -82,7 +82,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Brioche
         uses: ./ # Uses an action in the root directory