Bump actions/checkout from 5 to 6 (#243)

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/deploy.yml

@@ -28,7 +28,7 @@ jobs:
         python-version: '3.10'
 
     - name: clone sorunlib
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: install build dependencies
       run: |

.github/workflows/pytest.yml

@@ -28,7 +28,7 @@ jobs:
         python-version: ${{ matrix.python }}
 
     - name: clone sorunlib
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Lint with flake8
       run: |