docs: update badge styles in README.md

Author: haithium

README.md

@@ -1,10 +1,10 @@
 # evdev
 
-[![LuaRocks](https://img.shields.io/luarocks/v/BlueLua/bluelua-evdev?color=blue)](https://luarocks.org/modules/BlueLua/bluelua-evdev)
-[![Test Status](https://github.com/BlueLua/evdev/actions/workflows/test.yml/badge.svg)](https://github.com/BlueLua/evdev/actions/workflows/test.yml)
-![Lua Versions](https://img.shields.io/badge/lua-5.1%20%7C%205.2%20%7C%205.3%20%7C%205.4%20%7C%205.5%20%7C%20LuaJIT-blue)
-![Platform](https://img.shields.io/badge/platform-linux-lightgrey)
-[![License](https://img.shields.io/github/license/BlueLua/evdev?color=lightgrey)](LICENSE)
+[![LuaRocks](https://img.shields.io/luarocks/v/BlueLua/bluelua-evdev?color=blue&style=flat-square)](https://luarocks.org/modules/BlueLua/bluelua-evdev)
+[![Test Status](https://img.shields.io/github/actions/workflow/status/BlueLua/evdev/test.yml?style=flat-square)](https://github.com/BlueLua/evdev/actions/workflows/test.yml)
+![Lua Versions](https://img.shields.io/badge/lua-5.1%20%7C%205.2%20%7C%205.3%20%7C%205.4%20%7C%205.5%20%7C%20LuaJIT-blue?style=flat-square)
+![Platform](https://img.shields.io/badge/platform-linux-blue?style=flat-square)
+[![License](https://img.shields.io/badge/license-MIT-blue?style=flat-square)](https://github.com/BlueLua/evdev/blob/main/LICENSE)
 
 Lua bindings for Linux `evdev` input devices and `/dev/uinput` virtual devices
 (keyboards, mice, and relative pointers).