Pre-compiled popperjs core
npm install @vant/popperjs
@popperjs/core in commonjs format, added Object.assign polyfill.
``shellwith npmnpm i @vant/popperjs
shellwith npmnpm i @vant/popperjs
see: https://popper.js.org/
issue: https://github.com/vant-ui/vant/issues/7626