Add support for the cpp stdlib in TheCherno/imgui fork

[StevenSavold]

Is your feature request related to a problem? Please describe

I would like to use std::string's with my ImGui widgets when developing applications with Hazel.

Describe the solution you'd like

I would like to add the following two line to the premake5.lua inside of the "files" section: "misc/cpp/imgui_stdlib.cpp", "misc/cpp/imgui_stdlib.h"

Describe alternatives you've considered

Alternatively, I could fork Hazel and change the dependency on ImGui to a new fork of ImGui I would then have to make myself with the appropriate changes to the premake5.lua file

Additional context

None

[StevenSavold]

I have created a pull request with the changes mentioned in this issue in TheCherno/imgui fork. That PR can be found here https://github.com/TheCherno/imgui/pull/13