Add vue 2.7 feature

[billyct]

https://blog.vuejs.org/posts/vue-2-7-naruto.html

With vue 2.7 released, so i try to upgrade my app to vue 2.7.

and followed the upgrade guide, after I removed the package vue-template-compiler

Upgrade vue to ^2.7.0. You can also remove vue-template-compiler from the dependencies - it is no longer needed in 2.7.

it shows me the error

Error: Install vue-template-compiler to use enableVueLoader(  )
yarn add vue-template-compiler --dev

so add a special feature named vue2.7