Display build duration after build complete

[zuibunan]

What problem does this feature solve?

I want to see the build duration of my project

but now it only prints Build complete. The directory is ready to be deployed in the end.

no information about build time

What does the proposed API look like?

just prints Build complete for xx seconds. The directory is ready to be deployed in the end.`

[IndexXuan]

yarn build is ok