README: add more badges (pingcap#96)

Signed-off-by: Neil Shen <overvenus@gmail.com>

README.md

@@ -1,13 +1,19 @@
 # BR
 
 [![Build Status](https://internal.pingcap.net/idc-jenkins/job/build_br_master/badge/icon)](https://internal.pingcap.net/idc-jenkins/job/build_br_master/)
+[![codecov](https://codecov.io/gh/pingcap/br/branch/master/graph/badge.svg)](https://codecov.io/gh/pingcap/br)
+[![LICENSE](https://img.shields.io/github/license/pingcap/br.svg)](https://github.com/pingcap/br/blob/master/LICENSE)
+[![Language](https://img.shields.io/badge/Language-Go-blue.svg)](https://golang.org/)
+[![GoDoc](https://img.shields.io/badge/Godoc-reference-blue.svg)](https://godoc.org/github.com/pingcap/br)
+[![Go Report Card](https://goreportcard.com/badge/github.com/pingcap/br)](https://goreportcard.com/report/github.com/pingcap/br)
+[![GitHub release](https://img.shields.io/github/tag/pingcap/br.svg?label=release)](https://github.com/pingcap/br/releases)
+[![GitHub release date](https://img.shields.io/github/release-date/pingcap/br.svg)](https://github.com/pingcap/br/releases)
 
 **Backup & Restore (BR)** is a command-line tool for distributed backup and restoration of the TiDB cluster data.
 
 ## Architecture
 
-![architecture](https://raw.githubusercontent.com/pingcap/docs/891bcb480bf9441b4db3457989eb4ea77dfd38b5/media/br-arch.png)
-
+<img src="images/arch.svg?sanitize=true" alt="architecture" width="600"/>
 
 ## Documentation