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]>

.github/workflows/ruby-tests.yml

@@ -27,15 +27,15 @@ jobs:
     steps:
       - uses: actions/checkout@v3
 
-      - uses: actions/cache@v3
+      - uses: actions/cache@v4
         id: bundler-cache
         with:
           path: vendor/bundle
           key: >
             ${{ runner.os }}-${{ matrix.ruby }}-gems-${{
             hashFiles(matrix.gemfile) }}
 
-      - uses: actions/cache@v3
+      - uses: actions/cache@v4
         id: npm-cache
         with:
           path: vendor/bundle