docs: update license badage url

Signed-off-by: i-curve <[email protected]>

README.md

@@ -3,7 +3,7 @@
 [![cMake on multiple platforms](https://github.com/i-curve/copypp/actions/workflows/cmake-multi-platform.yml/badge.svg)](https://github.com/i-curve/copypp/actions/workflows/cmake-multi-platform.yml)
 [![Vcpkg Version](https://img.shields.io/vcpkg/v/copypp)](https://vcpkg.link/ports/copypp)
 [![Conan Center](https://img.shields.io/conan/v/copypp)](https://conan.io/center/recipes/copypp)
-[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/nlohmann/json/master/LICENSE.MIT)
+[![GitHub license](https://img.shields.io/badge/license-MIT-blue.svg)](https://github.com/i-curve/copypp/raw/master/LICENSE)
 
 support field copy in different c++ data type.