Drop spec for mixed keys in hash since it fails on 2.6
Drop spec for mixed keys in hash since it fails on 2.6

So, ruby doesn't allow passing symbols with strings when a method has keywords.
That's fair because it's a smell IMO. However, it breaks the spec ensuring the
previous behavior so I decided to drop it.

dry-rb/dry-monads,dry-rb/dry-monads,dry-rb/dry-monads