v1.2.0 of coverflow_carousel

A highly customizable 3D coverflow-style carousel for Flutter with smooth animations, perspective effects, and controller support. Changelog excerpt: 1. Center Card Overlay: Added centerOverlayBuilderto CoverflowCarousel.builderallowing custom overlay widgets (such as play buttons, badges, or tags) to be stacked on the active centered card. 2. Smooth Fade Transition: The center overlay automatically fades in and out smoothly using a scroll-linked opacity calculation based on the card's distance from the center. 3. Flexible Positioning: Developers can use standard Flutter alignment and layout widgets (Align, `Positione[...]