add codacy badge

README.md

@@ -8,6 +8,7 @@
 [![GitHub Test Badge](https://github.com/v2fly/v2ray-core/workflows/Test/badge.svg)](https://github.com/v2fly/v2ray-core/actions)
 [![codecov.io](https://codecov.io/gh/v2fly/v2ray-core/branch/master/graph/badge.svg?branch=master)](https://codecov.io/gh/v2fly/v2ray-core?branch=master)
 [![codebeat](https://goreportcard.com/badge/github.com/v2fly/v2ray-core)](https://goreportcard.com/report/github.com/v2fly/v2ray-core)
+[![Codacy Badge](https://app.codacy.com/project/badge/Grade/e150b7ede2114388921943bf23d95161)](https://www.codacy.com/gh/v2fly/v2ray-core/dashboard?utm_source=github.com&utm_medium=referral&utm_content=v2fly/v2ray-core&utm_campaign=Badge_Grade)
 [![Downloads](https://img.shields.io/github/downloads/v2fly/v2ray-core/total.svg)](https://github.com/v2fly/v2ray-core/releases/latest)
 
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