cocoapods not be updated，May be due to damage caused local database，We can go directly to CocoaPods local directory manually update it：
git checkout master
And then return to the implementation of the project to normal under update .
Original article written by Gerber drop-off：R0uter's Blog » CocoaPods was not able to update the `master` repo.
Reproduced Please keep the source and description link：https://www.logcg.com/archives/3051.html