Babel-core: make it a peerDep

[hzoo]

So that you can use a different version (v7)

I guess the only issue is how that would work with npx or a global install..

[eventualbuddha]

Isn't v7 a fairly different API?

[hzoo]

Uh the api meaning like babel-core stuff is basically the same? If you mean the AST, some things are a little different but those are for the experimental nodes/proposals anyway. But yeah not sure about how this will work with npx anyway @loganfsmyth and given #53

[eventualbuddha]

codemod now uses babel 7.x, so I'm going to close this.