Change Request: Move @types/ssh2 devDependency to regular dependency

[cinderblock]

Since this package publishes TypeScript types directly and doesn't rely on DefinitelyTyped, I think the dependency on @types/ssh2 should be a normal dependency. I think it's slightly confusing that half of the types don't work after installing ssh2-promise.

If this change were implemented, it would be slightly easier to use out of the box. Granted, the normal "fix" is to simply install @types/ssh2 as well. This has the added benefit that one could chose to not export the types to really minify package sizes, but that seems rare in this case.

Would this be considered? Am I missing something?