chore(deps): bump actions/cache from 2.1.7 to 4.0.0

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.7 to 4.0.0.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v2.1.7...v4.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/pr.yaml

@@ -42,7 +42,7 @@ jobs:
     - name: docker build
       run: docker build . --file Dockerfile --tag image
     - name: cached scan db
-      uses: actions/cache@v2.1.7
+      uses: actions/cache@v4.0.0
       with:
         path: vulndb/
         key: trivy-vulndb