Bump codecov/codecov-action from 2.1.0 to 3.1.0 (#537)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 2.1.0 to 3.1.0.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/master/CHANGELOG.md)
- [Commits](codecov/codecov-action@v2.1.0...v3.1.0)

---
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/main.yml

@@ -34,7 +34,7 @@ jobs:
       run: go test -p 1 -coverpkg ./... -covermode atomic -coverprofile coverage.txt ./...
 
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v2.1.0
+      uses: codecov/codecov-action@v3.1.0
       if: matrix.os == 'ubuntu-latest'
       with:
         token: ${{ secrets.CODECOV_TOKEN }}