Update actions/cache action to v4 (#6)

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

Author: renovate[bot]

.github/workflows/lint.yaml

@@ -30,7 +30,7 @@ jobs:
 
       - name: Load cached venv
         id: cached-poetry-dependencies
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: .venv
           key: venv-${{ runner.os }}-${{ steps.setup-python.outputs.python-version }}-${{ hashFiles('**/poetry.lock') }}