Complir joined Y Combinator with 10 employees and $200k ARR. Co-Founder and CEO Gustav Bang told us how more mature startups can use YC as a growth lever: "We already had salespeople, we already had developers in place, so we could use YC to accelerate what we were already doing and show revenue." "We came in with 200k yearly revenue and went out with 800k, so it was a good success for us." "It was kind of a strategic thing to do, and I think more companies are looking at doing that, using…