Add blue_engine_egui to third party integrations

Greetings!

Author of [Blue Engine](https://github.com/AryanpurTech/BlueEngine) here, I've recently built an egui [plugin](https://github.com/AryanpurTech/BlueEngineEGUI) for my engine that enables users to add egui to their projects easily.

I was wondering if it can be added to the egui's list of third party integrations or libraries that use egui.

Thanks,

Inspect egui's third-party integrations or libraries list and its surrounding entries to find the appropriate documentation location and link format. Add Blue Engine's egui integration using the URLs in the issue, then verify the list renders and the link works.

Written by the indexing model from the issue text.