readme: added code coverage badge
@@ -5,8 +5,7 @@ Kopia
[![Build Status](https://github.com/kopia/kopia/workflows/Build/badge.svg)](https://github.com/kopia/kopia/actions?query=workflow%3ABuild)
[![Slack](https://img.shields.io/badge/discuss-slack-blue.svg)](https://slack.kopia.io/)
[![GoDoc](https://godoc.org/github.com/kopia/kopia/repo?status.svg)](https://godoc.org/github.com/kopia/kopia/repo)
-[![Coverage Status](https://coveralls.io/repos/github/kopia/kopia/badge.svg?branch=master)](https://coveralls.io/github/kopia/kopia?branch=master)
-[![Go Report Card](https://goreportcard.com/badge/github.com/kopia/kopia)](https://goreportcard.com/report/github.com/kopia/kopia)
+[![Coverage Status](https://codecov.io/gh/kopia/kopia/branch/master/graph/badge.svg?token=CRK4RMRFSH)](https://codecov.io/gh/kopia/kopia)[![Go Report Card](https://goreportcard.com/badge/github.com/kopia/kopia)](https://goreportcard.com/report/github.com/kopia/kopia)
[![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-v2.0%20adopted-ff69b4.svg)](CODE_OF_CONDUCT.md)
> _n._
