Bump codecov/codecov-action from 2.0.3 to 2.1.0

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 2.0.3 to 2.1.0.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/master/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-action/compare/v2.0.3...v2.1.0)

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

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

.github/workflows/main.yml

@@ -72,4 +72,4 @@ jobs:
       - name: Generate code coverage
         run: cargo llvm-cov --all-features --lcov > lcov.info
       - name: Upload coverage report to Codecov
-        uses: codecov/codecov-action@v2.0.3
+        uses: codecov/codecov-action@v2.1.0