[ci] Bump actions/cache from 2 to 4

Bumps [actions/cache](https://github.com/actions/cache) from 2 to 4.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v2...v4)

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

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

.github/workflows/ci.yml

@@ -23,7 +23,7 @@ jobs:
         run: echo "::set-output name=dir::$(yarn cache dir)"
 
       - name: Cache yarn
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         id: yarn-cache
         with:
           path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
@@ -55,7 +55,7 @@ jobs:
         run: echo "::set-output name=dir::$(yarn cache dir)"
 
       - name: Cache yarn
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         id: yarn-cache
         with:
           path: ${{ steps.yarn-cache-dir-path.outputs.dir }}