:arrow_up: RxCocoa version up (#368)

[ryo-otake-sonix]

Description: Swift_version was added to RIBs.podspec for prebuilding RIBs by PodBuilder.

Related issue(s):

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

:white_check_mark: ElonPark
:x: ryo-otake-sonix
_{You have signed the CLA already but the status is still pending? Let us recheck it.}