fix: noDupeKeys ignores ObjectTypeSpreadProperty

[uforic]

The new object type spread features in Flow cause the noDupeKeys rule to crash. Specifically, .value is accessed on the ObjectTypeSpreadProperty node, which doesn't have that field.

type Foo = {...Bar}; // this would crash noDupeKeyes

The workaround is to use the Flow commenting syntax, like this:
/**
type Foo = {...Bar};
*/

I'd love to write tests (and had, in fact), but due to some combination of babylon, babel-eslint, and babel-cli, the object type spread syntax wasn't recognized and would fail tests (most immediately caused by babel-eslint). I tried bumping versions, but ended up going down a bit of a rabbit hole because other tests began failing. Seems like a general version bump refresh is in order.

Would appreciate any feedback, thanks!