Update actions/cache action to v6 (#1677)

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

Author: renovate[bot]

.github/workflows/ci.yml

@@ -25,7 +25,7 @@ jobs:
       - run: pip install -r requirements.txt -r requirements-dev.txt
       - name: Run template rendering tests
         run: pytest -q -ra tests/templates
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         with:
           path: vendor
           key: ${{ runner.os }}-galaxy-${{ hashFiles('galaxy.yml') }}