Bump actions/cache from 4 to 5 (#20)

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -31,7 +31,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
 
       - name: Cache pip
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ~/.cache/pip
           key: ${{ runner.os }}-pip-${{ hashFiles('**/pyproject.toml') }}