docs(README): add npm badge

Author: Fonger

README.md

@@ -1,6 +1,6 @@
 # ts-transformer-optimize-const-enum
 
-![CI Status](https://github.com/Fonger/ts-transformer-optimize-const-enum/actions/workflows/build.yml/badge.svg)
+[![](https://img.shields.io/npm/v/ts-transformer-optimize-const-enum.svg)](https://www.npmjs.com/package/ts-transformer-optimize-const-enum) ![CI Status](https://github.com/Fonger/ts-transformer-optimize-const-enum/actions/workflows/build.yml/badge.svg)
 
 A typescript transpiler that transform exported const enum into object literal.