Bump tj-actions/changed-files from 18.7 to 19

Bumps [tj-actions/changed-files](https://github.com/tj-actions/changed-files) from 18.7 to 19.
- [Release notes](https://github.com/tj-actions/changed-files/releases)
- [Changelog](https://github.com/tj-actions/changed-files/blob/main/HISTORY.md)
- [Commits](https://github.com/tj-actions/changed-files/compare/v18.7...v19)

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

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

.github/workflows/reusable-ci-backend.yml

@@ -87,7 +87,7 @@ jobs:
       -
         name: Get changed files
         id: changed-files-specific
-        uses: tj-actions/changed-files@v18.7
+        uses: tj-actions/changed-files@v19
         with:
           files: |
             src/**