Update actions/checkout action to v6 (#388)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/coverage.yml

@@ -11,7 +11,7 @@ jobs:
     env:
       PYTHON: '3.9'
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup Python
       uses: actions/setup-python@v5
       with: