Bump codecov/codecov-action from 1.5.2 to 2.1.0

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 1.5.2 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](codecov/codecov-action@v1.5.2...v2.1.0)

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

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

.github/workflows/test.yml

@@ -16,6 +16,6 @@ jobs:
       - run: make build
       - run: |
           go test ./... -mod=readonly -timeout 8m -race -coverprofile=coverage.txt -covermode=atomic
-      - uses: codecov/codecov-action@v1.5.2
+      - uses: codecov/codecov-action@v2.1.0
         with:
           file: ./coverage.txt