[Cocoapods] Fix podspec to include swift files
[Cocoapods] Fix podspec to include swift files

YuanZhu-apple/ResearchKit,mluedke2/ResearchKit,weijentu/ResearchKit,YuanZhu-apple/ResearchKit,cornelltech/ResearchKit,md0u80c9/ResearchKit,chb/ResearchKit,boland25/ResearchKit,chb/ResearchKit,chb/ResearchKit,cornelltech/ResearchKit,YuanZhu-apple/ResearchKit,boland25/ResearchKit,oliverschaefer/ResearchKit,weijentu/ResearchKit,md0u80c9/ResearchKit,chb/ResearchKit,mluedke2/ResearchKit,jeremiahyan/ResearchKit,md0u80c9/ResearchKit,cornelltech/ResearchKit,mluedke2/ResearchKit,YuanZhu-apple/ResearchKit,boland25/ResearchKit,md0u80c9/ResearchKit,jeremiahyan/ResearchKit,weijentu/ResearchKit,jeremiahyan/ResearchKit,weijentu/ResearchKit,oliverschaefer/ResearchKit,oliverschaefer/ResearchKit,oliverschaefer/ResearchKit,boland25/ResearchKit