ESM support

[Heartnett]

@antfu Thanks for this awesome project!

Currently v0.14.11 is causing this issue:

failed to load config from .....\vite.config.ts
error when starting dev server:
file:///...../node_modules/.pnpm/unplugin-vue-components@0.14.11_vite@2.5.3+vue@2.6.14/node_modules/unplugin-vue-components/dist/chunk-EDKGX5IJ.mjs:348
import { sync as resolve } from "resolve";
^^^^
SyntaxError: Named export 'sync' not found. The requested module 'resolve' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'resolve';
const { sync: resolve } = pkg;

at ModuleJob._instantiate (internal/modules/esm/module_job.js:121:21)
at async ModuleJob.run (internal/modules/esm/module_job.js:166:5)
at async Loader.import (internal/modules/esm/loader.js:178:24)
at async loadConfigFromFile (.....\node_modules\.pnpm\vite@2.5.3\node_modules\vite\dist\node\chunks\dep-1be34a63.js:77045:31)
at async resolveConfig (.....\node_modules\.pnpm\vite@2.5.3\node_modules\vite\dist\node\chunks\dep-1be34a63.js:76656:28)
at async createServer (.....\node_modules\.pnpm\vite@2.5.3\node_modules\vite\dist\node\chunks\dep-1be34a63.js:75179:20)
at async CAC.<anonymous> (.....\node_modules\.pnpm\vite@2.5.3\node_modules\vite\dist\node\cli.js:14007:24)

 ERROR  Command failed with exit code 1.

I think this commit may be the cause: da8740b
https://github.com/antfu/unplugin-vue-components/blob/da8740bd800fe8f3e19e111826553b390a251cbd/src/core/utils.ts#L5