Update README.md
add codecov.io badge
@@ -7,8 +7,7 @@ cli
[![GoDoc](https://godoc.org/github.com/urfave/cli?status.svg)](https://godoc.org/github.com/urfave/cli)
[![codebeat](https://codebeat.co/badges/0a8f30aa-f975-404b-b878-5fab3ae1cc5f)](https://codebeat.co/projects/github-com-urfave-cli)
[![Go Report Card](https://goreportcard.com/badge/urfave/cli)](https://goreportcard.com/report/urfave/cli)
-[![top level coverage](https://gocover.io/_badge/github.com/urfave/cli?0 "top level coverage")](http://gocover.io/github.com/urfave/cli) /
-[![altsrc coverage](https://gocover.io/_badge/github.com/urfave/cli/altsrc?0 "altsrc coverage")](http://gocover.io/github.com/urfave/cli/altsrc)
+"[![codecov](https://codecov.io/gh/urfave/cli/branch/master/graph/badge.svg)](https://codecov.io/gh/urfave/cli)"
This is the library formerly known as `github.com/codegangsta/cli` -- Github
will automatically redirect requests to this repository, but we recommend
