dry-rb 1.0: upgrading validations, types and schemas

I’m enthusiastic about dry-rb gems. Actually, I’ve never worked on Ruby projects without a dry-rb gem. However, some people are sceptical, as a lot of core dry-rb gems are still in their 0.x phase, which leads to a lot of breaking changes and hours of refactoring.I’m happy to see dry-rb mature: dry-monads entered 1.0 phase in Summer 2018, and now two more libraries hit v1.0 milestones: dry-types and dry-struct.