RxJava1->2로 이동시 유의해야할 내용 링크

Our Top Nine Learnings from Migrating from RxJava 1 to RxJava 2

https://www.runtastic.com/blog/en/tech/rxjava-2-migration-learnings/?utm_source=Android+Weekly&utm_campaign=e254d2512b-androidweekly-285&utm_medium=email&utm_term=0_4eb677ad19-e254d2512b-338106413