can you please mention dependency on rapidjson

[Rohit Vishwakarma]

Hi, Can you please mention dependency on rapidjson in the documentation. I was on latest version of rapidjson installed separately via vcpkg(windows) or normal(linux), however it caused loads of link error and took me a while to figure it out.

After I removed rapidjson folder from staticjson, everything worked correctly. Hopefully this will help some one. If possible, please simply remove rapidjson folder and ask users to install separately.

Thanks a lot for the library.

[Siyuan Ren]

Done.

[Rohit Vishwakarma]

thanks a lot!