ci(deps): bump actions/cache from 5 to 6

Bumps [actions/cache](https://github.com/actions/cache) from 5 to 6.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v5...v6)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ jobs:
   download_test_data:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/cache@v5
+      - uses: actions/cache@v6
         id: cache
         with:
           key: raw_test_data # fixed key will always hit; clear cache to trigger cache miss
@@ -187,7 +187,7 @@ jobs:
       - uses: actions/download-artifact@v8
         with:
           name: build_ubuntu-latest
-      - uses: actions/cache/restore@v5
+      - uses: actions/cache/restore@v6
         with:
           key: raw_test_data
           path: |
@@ -216,7 +216,7 @@ jobs:
       - uses: actions/download-artifact@v8
         with:
           name: build_ubuntu-latest
-      - uses: actions/cache/restore@v5
+      - uses: actions/cache/restore@v6
         with:
           key: raw_test_data
           path: |