Bump actions/cache from 4 to 5 (#118)

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 5.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/unit-test.yaml

@@ -65,7 +65,7 @@ jobs:
           path: component
       - name: Restore cached HOOMD-blue build
         id: cache
-        uses: actions/cache/restore@v4
+        uses: actions/cache/restore@v5
         with:
           path: install
           key: hoomd-blue-${{ env.HOOMD_BLUE_VERSION }}-mpi-${{ matrix.enable_mpi }}-gpu-${{ matrix.enable_gpu }}
@@ -112,7 +112,7 @@ jobs:
         working-directory: build-hoomd-blue
       - name: Cache HOOMD-blue build
         if: steps.cache.outputs.cache-hit != 'true'
-        uses: actions/cache/save@v4
+        uses: actions/cache/save@v5
         with:
           path: install
           key: hoomd-blue-${{ env.HOOMD_BLUE_VERSION }}-mpi-${{ matrix.enable_mpi }}-gpu-${{ matrix.enable_gpu }}