higher deployment target version

support 0.23

update pod spec

Add support for componentkit 0.20

This release is updated for componentkit 0.20.While 0.20 have no
official release in
cocoapods, a git repo could be specifid in podfile to solve this
problem. One option is 'https://github.com/leavez/componentkit.git'.

If you use componentkit 0.15.1, please use 0.1 version.

initial release