fix: Change main file in package.json

Author: znck

package.json

@@ -12,8 +12,7 @@
     "vue"
   ],
   "license": "MIT",
-  "main": "dist/rollup-plugin-vue.common.js",
-  "module": "dist/rollup-plugin-vue.js",
+  "main": "dist/index.js",
   "repository": {
     "type": "git",
     "url": "git+https://github.com/znck/rollup-plugin-vue.git"