Bump actions/checkout from 5 to 6 (#417)

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/audit.yaml

@@ -19,7 +19,7 @@ jobs:
   security_audit:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions-rs/audit-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/coverage.yml

@@ -18,7 +18,7 @@ jobs:
   tests-coverage:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install build dependencies
         run: bash .github/workflows/install-dependencies
       - name: Setup toolchain (coverage)

.github/workflows/format.yaml

@@ -19,7 +19,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install build dependencies
         run: bash .github/workflows/install-dependencies
       - name: Setup toolchain (coverage)

.github/workflows/rust.yaml

@@ -28,7 +28,7 @@ jobs:
           - ubuntu:latest
         stable: [true]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install build dependencies
         run: bash .github/workflows/install-dependencies
       - name: Setup toolchain (coverage)

.github/workflows/spellcheck.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Check Spelling
         uses: rojopolis/spellcheck-github-actions@0.54.0
         with:

.github/workflows/yamllint.yaml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: 'Checkout'
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: 'Yamllint'
         uses: karancode/yamllint-github-action@master
         with: