Bump codecov/codecov-action from 3 to 4 (#13)

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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci.yml

@@ -55,9 +55,10 @@ jobs:
           bundle exec rake coverage
 
       - name: Upload coverage report
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v4
         with:
           name: ${{ runner.os }}-${{ matrix.ruby }}-frozen_string_literal-${{ matrix.frozen_string_literal }}
           file: ./coverage/coverage.xml
-          token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}