Add common dependencies

[ErikSchierboom]

This PR pre-loads the following dependencies:

• QuickCheck
• lens
• parallel
• vector
• split
• random
• string-conversions

See exercism/haskell#1006

[iHiD]

Nice.

[ErikSchierboom]

@petertseng Does this look okay to you?

[petertseng]

Well... the list of dependencies is exactly what I suggested, so from that perspective that can't have any complaints. So now we have to think of other angles.

I'm wondering, would it be a good idea or a bad idea to add a comment explaining, for each dependency, why it's in this list? Right now I don't yet see a reason to do that. Perhaps that idea will become useful when this list of dependencies is audited later on and the maintainers of the test runner have to decide whether to keep or dump a given dependency, but since this list is just starting nobody is sure when that will happen. But let us remember that idea for later.

I have of course no way of knowing whether adding those dependencies to this list here will actually solve the problems, but that is supposedly easy to test - submit a solution to diamond before and after and see if there are differences in the result.

[ErikSchierboom]

I'm wondering, would it be a good idea or a bad idea to add a comment explaining, for each dependency, why it's in this list? Right now I don't yet see a reason to do that. Perhaps that idea will become useful when this list of dependencies is audited later on and the maintainers of the test runner have to decide whether to keep or dump a given dependency, but since this list is just starting nobody is sure when that will happen. But let us remember that idea for later.

I agree. In the future, it is probably best to have a separate document listing all the dependencies, as then the test runner code itself could parse any errors and remarkt that the student can only use one of the supported dependencies.

[ErikSchierboom]

@petertseng I've just run the tests on my dnd-character solution (which uses QuickCheck), and it worked!