Bump actions/cache from 4 to 5

Bumps [actions/cache](https://github.com/actions/cache) from 4 to 5.
- [Release notes](https://github.com/actions/cache/releases)
- [Changelog](https://github.com/actions/cache/blob/main/RELEASES.md)
- [Commits](actions/cache@v4...v5)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/pr.yaml

@@ -83,7 +83,7 @@ jobs:
 
       - name: Cache Docker images
         id: docker-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: /tmp/docker-images
           key: docker-images-${{ env.PG_DOCKER_IMAGE }}-${{ env.MYSQL_DOCKER_IMAGE }}