Merge pull request #1 from graffer-inc/2024-01-25-action-cache

CI: update action/cache to v4

.github/workflows/test.yml

@@ -18,7 +18,7 @@ jobs:
       uses: actions/setup-python@v2
       with:
         python-version: ${{ matrix.python-version }}
-    - uses: actions/cache@v2
+    - uses: actions/cache@v4
       with:
         path: ~/.cache/pip
         key: pip-test-${{ matrix.python-version }}-${{ matrix.os }}