DEP: Bump actions/cache from 5 to 6 (#22)

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

Author: dependabot[bot]

.github/workflows/build.yml

@@ -48,7 +48,7 @@ jobs:
           if-no-files-found: error
 
       - name: Save cache
-        uses: actions/cache/save@v5
+        uses: actions/cache/save@v6
         with:
           path: ${{ github.workspace }}
           key: plugin
@@ -92,7 +92,7 @@ jobs:
       changes: ${{ needs.changes.outputs.changes }}
     steps:
       - name: Restore cache
-        uses: actions/cache/restore@v5
+        uses: actions/cache/restore@v6
         with:
           path: ${{ github.workspace }}
           key: plugin