chore: add icon

Author: lisonge

README.md

@@ -1,5 +1,8 @@
 # kotlin-json5
 
+[![Maven Central](https://img.shields.io/maven-central/v/li.songe/json5.svg?label=Maven%20Central)](https://central.sonatype.com/artifact/li.songe/json5)
+[![License](http://img.shields.io/:License-Apache-blue.svg)](http://www.apache.org/licenses/LICENSE-2.0.html)
+
 kotlin multiplatform json5 for [kotlinx.serialization](https://github.com/Kotlin/kotlinx.serialization)
 
 supports: jvm, Android, linux, Windows, macOS, iOS, watchOS, tvOS