chore: upload apisix logo image (apache#2371)

added link in readme.

README.md

@@ -17,7 +17,8 @@
 #
 -->
 
-[Chinese](README_CN.md)
+- [Chinese](README_CN.md)
+
 ## APISIX
 
 [![Build Status](https://travis-ci.org/apache/apisix.svg?branch=master)](https://travis-ci.org/apache/apisix)
@@ -291,6 +292,11 @@ APISIX enriches the <a href="https://landscape.cncf.io/category=api-gateway&form
 CNCF API Gateway Landscape.</a>
 </p>
 
+## Logos
+
+- [Apache APISIX logo(PNG)](logos/apache-apisix.png)
+- [Apache APISIX logo source](https://apache.org/logos/#apisix)
+
 ## Contributing
 
 See [CONTRIBUTING](CONTRIBUTING.md) for details on submitting patches and the contribution workflow.

README_CN.md

@@ -17,7 +17,8 @@
 #
 -->
 
-[English](README.md)
+- [English](README.md)
+
 ## APISIX
 
 [![Build Status](https://travis-ci.org/apache/apisix.svg?branch=master)](https://travis-ci.org/apache/apisix)
@@ -294,6 +295,11 @@ Dashboard 默认只允许 127.0.0.1 访问。你可以自行修改 `conf/config.
 APISIX 被纳入 <a href="https://landscape.cncf.io/category=api-gateway&format=card-mode&grouping=category"> 云原生软件基金会 API 网关全景图</a>
 </p>
 
+## Logo
+
+- [Apache APISIX logo(PNG)](logos/apache-apisix.png)
+- [Apache APISIX logo 源文件](https://apache.org/logos/#apisix)
+
 ## 致谢
 
 灵感来自 Kong 和 Orange。