Update actions/cache action to v5 (#731)

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

Author: renovate[bot]

.github/workflows/build.yml

@@ -20,7 +20,7 @@ jobs:
         run: make poetry-download
 
       - name: Set up cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: .venv
           key: venv-${{ matrix.python-version }}-${{ hashFiles('pyproject.toml') }}-${{ hashFiles('poetry.lock') }}