Bump codecov/codecov-action from 3 to 4

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 3 to 4.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v3...v4)

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

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

.github/workflows/testing.yml

@@ -37,7 +37,7 @@ jobs:
           poetry run coverage run --source=mytoyota/ -m pytest
           poetry run coverage xml
       - name: "⬆️ Upload Coverage to Codecov"
-        uses: "codecov/codecov-action@v3"
+        uses: "codecov/codecov-action@v4"
         with:
           token: "${{ secrets.CODECOV_TOKEN }}"
           env_vars: OS,PYTHON