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] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yaml

@@ -131,7 +131,7 @@ jobs:
       # https://github.com/docker/build-push-action/issues/252
       # https://github.com/moby/buildkit/issues/1896
       - name: Cache container layers
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: /tmp/.buildx-cache
           key: ${{ runner.os }}-buildx-nox-${{ matrix.arch }}-${{ matrix.os }}-${{ matrix.python }}
@@ -156,7 +156,7 @@ jobs:
 
       # Cache pip downloads
       - name: Cache pip downloads
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: /tmp/pip-cache
           key: nox-${{ matrix.nox-session }}-${{ matrix.arch }}-${{ matrix.os }}-${{ matrix.python }}-${{ hashFiles('**/pyproject.toml') }}