Bump actions/cache from 3 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 3 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v3...v4)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Setup conda cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/conda_pkgs_dir
           key:
@@ -34,7 +34,7 @@ jobs:
           use-only-tar-bz2: true
           use-mamba: true
       - name: Setup hypothesis DB cache
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ./.hypothesis
           key: hypothesisDB ${{ matrix.PYTHON_VERSION }}