ci: bump codecov/codecov-action from 5.1.2 to 5.3.1

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5.1.2 to 5.3.1.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v5.1.2...v5.3.1)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -128,7 +128,7 @@ jobs:
 
       - name: "Upload general coverage to Codecov"
         if: ${{ matrix.backend_dir_name == 'the_simplest_backend' }}
-        uses: codecov/codecov-action@v5.1.2
+        uses: codecov/codecov-action@v5.3.1
         with:
           name: codecov-general
           files: ./tests/${{ matrix.backend_dir_name }}_coverage.xml
@@ -137,7 +137,7 @@ jobs:
 
       - name: "Upload ml-backend ${{ matrix.backend_dir_name }} coverage to Codecov"
         if: ${{ matrix.backend_dir_name == 'the_simplest_backend' }}
-        uses: codecov/codecov-action@v5.1.2
+        uses: codecov/codecov-action@v5.3.1
         with:
           name: codecov-${{ matrix.backend_dir_name }}
           files: ./label_studio_ml/examples/${{ matrix.backend_dir_name }}/coverage.xml