[docs] Add download link to readme for development preview

Author: Breakthrough

README.md

@@ -1,3 +1,7 @@
+## `opencv-python-cuda`
+
+Download: [Latest Release (4.12.0-dev0)](https://github.com/Breakthrough/opencv-python-cuda/releases/tag/4.12.0-dev0)
+
 ## What is `opencv-python-cuda`?
 
 Pre-built NVIDIA® CUDA™ enabled OpenCV packages for Python that come with all batteries included. This is a fork of [the official opencv-python project](https://github.com/opencv/opencv-python). Right now packages are only produced for Windows x64, and devices must be Maxwell class (GeForce 900 series) or newer.  Once installed via `pip` (or another Python package manager like `uv`), the following should *just work*: