fix(types): explicitly define "types" field

Explicitly define "types" field

Author: breakingrobot

package.json

@@ -2,6 +2,7 @@
   "name": "nuxt-class-component",
   "version": "1.2.0",
   "main": "./dist/index.js",
+  "types": "./dist/index.d.ts",
   "repository": "https://github.com/nuxt-community/nuxt-class-component.git",
   "license": "MIT",
   "scripts": {