v0.1.2 of flutter_deepar

Flutter plugin for the DeepAR augmented reality SDK. Provides camera capture, AR effect loading/switching, and a stream of AR-processed frames (RGBA/BGRA) for use in live streaming, recording, or preview. Changelog excerpt: - Fix: Resolved a race condition on iOS and Android where startCapturecould crash in release mode due to asynchronous engine initialization. - Fix: Added ProGuard rules to prevent DeepAR classes from being stripped by R8 during release builds on Android.