⬆️ Bump actions/cache from 5 to 6 in the actions group (#316)

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

Author: dependabot[bot]

.github/workflows/docs.yml

@@ -18,7 +18,7 @@ jobs:
       - name: Setup Python environment
         uses: ./.github/actions/setup-python
 
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           key: mkdocs-material-${{ hashfiles('.cache/**') }}
           path: .cache