New plugin for supporting monorepos

[tunnckoCore]

What I'm thinking is to have a simple convention. Just list of changed packages inside the commit body, like so

feat: foo bar baz

The changed packages will be collected through `jest-changed-files`
and added as a list below (including the workspace directory name
in front of the changed package name).

packages:
- packages/recommended-bump
- @tunnckocore/execa
- packages/git-commits-since

Signed-off-by: Charlike Mike Reagent

Still not sure how it look like exactly, but we need such thing, definitely. I'll also suggest it to Conventional Commits, so we can come up some good convention together.

Above commit should bump listed packages to their next minor version.