The diversity is indeed an important issue. We thought about this and all of our job posts contain the following text: "Avoid the confidence gap; you do not have to match all the listed requirements exactly to apply.". Confidence gap links to http://www.theatlantic.com/magazine/archive/2014/05/the-conf...

For an example see https://about.gitlab.com/jobs/production-engineer/

Please let me know if you have any other suggestions.