chore: adjust readme & nycrc

.nycrc.json

@@ -6,8 +6,8 @@
     "coverage/**",
     "packages/*/tests/**",
     "packages/chai-extended/**",
-    "packages/plugin-*/src/database/**",
-    "packages/plugin-*/src/database.ts",
+    "packages/plugin-*/**/database/**",
+    "packages/plugin-*/**/database.js",
     "packages/plugin-mongo/**",
     "packages/plugin-mysql/**"
   ]

README.md

@@ -4,14 +4,16 @@
   </a>
   <h1 id="koishi"><a href="https://koishi.js.org/" target="_blank">Koishi</a></h1>
 
+[![Codecov](https://img.shields.io/codecov/c/github/koishijs/koishi?style=flat-square)](https://codecov.io/gh/koishijs/koishi)
+[![Language grade: JavaScript](https://img.shields.io/lgtm/grade/javascript/g/koishijs/koishi.svg?style=flat-square)](https://lgtm.com/projects/g/koishijs/koishi/context:javascript)
 [![npm](https://img.shields.io/npm/v/koishi?style=flat-square)](https://www.npmjs.com/package/koishi)
 [![GitHub](https://img.shields.io/github/license/koishijs/koishi?style=flat-square)](https://github.com/koishijs/koishi/blob/master/LICENSE)
 
 </div>
 
 Koishi 是一个在 [Node.js](https://nodejs.org/) 环境下运行的机器人框架，目前支持 [CQHTTP (OneBot)](https://github.com/howmanybots/onebot) 协议，未来也将支持更多平台。
 
-这个项目的名字和图标来源于东方 Project 中的角色古明地恋（Komeiji Koishi）。
+这个项目的名字和图标来源于东方 Project 中的角色古明地恋 (Komeiji Koishi)。
 
 ## 安装