Made change for C++17
Made change for C++17

When compiling for C++17, was getting an error about the to_string method not existing in json_wrapper.cpp. Detailed in issue #221. Fixed it by adding the necessary import statement to the file.

NoNamer64/sleepy-discord,yourWaifu/sleepy-discord,yourWaifu/sleepy-discord,NoNamer64/sleepy-discord,yourWaifu/sleepy-discord