docs(readme): fix npm badge

README.md

@@ -8,7 +8,7 @@
 # node-unrtf
 
 [![GitHub release](https://img.shields.io/github/release/Fdawgs/node-unrtf.svg)](https://github.com/Fdawgs/node-unrtf/releases/latest/)
-[![NPM version](https://img.shields.io/npm/v/node-unrtf)](https://npmjs.com/package/node-unrtf)
+[![npm version](https://img.shields.io/npm/v/node-unrtf)](https://npmjs.com/package/node-unrtf)
 [![Build status](https://github.com/Fdawgs/node-unrtf/actions/workflows/ci.yml/badge.svg?branch=main)](https://github.com/Fdawgs/node-unrtf/actions/workflows/ci.yml)
 [![Coverage status](https://coveralls.io/repos/github/Fdawgs/node-unrtf/badge.svg?branch=main)](https://coveralls.io/github/Fdawgs/node-unrtf?branch=main)
 [![code style: Prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg?style=flat)](https://github.com/prettier/prettier)