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/ci.yml

@@ -15,7 +15,7 @@ jobs:
         GITHUB_CONTEXT: ${{ toJson(github) }}
       run: echo "$GITHUB_CONTEXT"
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         fetch-depth: 0
     - name: Setup .NET versions
@@ -52,7 +52,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Fetch all history for all tags and branches
       run: git fetch --prune --unshallow
     - name: Install Mono (Ubuntu only)
@@ -88,7 +88,7 @@ jobs:
     if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Setup .NET versions
       uses: actions/setup-dotnet@v5
       with:

.github/workflows/codeql.yml

@@ -19,7 +19,7 @@ jobs:
 
     steps:
     - name: Checkout Repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Fetch all history for all tags and branches
       run: git fetch --prune --unshallow
     - name: Setup .NET versions