add transpiledependencies in vuepress

[xxholly32]

Feature request

What problem does this feature solve?

i always add dependenice in my vuepress demo，when i want to run at ie11; it will add same configuration in .vuepress/config.js, it`s a painful process;

it was sth like vue-cli transpiledependencies，it was great，i thougt maybe it could add in vuepress

What does the proposed API look like?

like vue-cli transpiledependencies

How should this be implemented in your opinion?

i think it should add some configration with babel-loader in @vuepress/core

Are you willing to work on this yourself?

yes