Add GitHub Downloads badge (#352)

Author: urikdev

README.md

@@ -3,6 +3,7 @@
 [![CI](https://github.com/urikdev/Urik/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/urikdev/Urik/actions/workflows/ci.yml)
 [![License: GPL v3](https://img.shields.io/badge/License-GPLv3-blue.svg)](https://www.gnu.org/licenses/gpl-3.0)
 [![Release](https://img.shields.io/github/v/release/urikdev/Urik?include_prereleases)](https://github.com/urikdev/Urik/releases)
+![GitHub Downloads (all assets, all releases)](https://img.shields.io/github/downloads/urikdev/Urik/total)
 
 Privacy-first keyboard for Android with on-device processing and encrypted storage. 100% community-funded, completely open-source.