Upgrade scalafix for build-in rules of OrganizeImports

It's using and better to update to https://github.com/scalacenter/sbt-scalafix which integrated the OrganizeImports in newer version.

>Important sort-imports does not (currently) take into account shadowing. It is a faily dumb sorter of imports. If your code is using shadowing, it may end up no longer compiling! If you run into this issue, consider using [liancheng/scalafix-organize-imports](https://github.com/liancheng/scalafix-organize-imports/), which implements a semantic rule.