团队开发中，经常会有人在pod里泡一个自己需要的三方，而在我们更新代码之后蛋疼的事情有时会是这样的：
pod install 不成功，提示：
$ pod install
Analyzing dependencies
[!] Unable to satisfy the following requirements:
-AliyunOSSiOS (~> 2.5.2) required by Podfile
None of your spec sources contain a spec satisfying the dependency: AliyunOSSiOS (~> 2.5.2).
You have either:
* out-of-date source repos which you can update with pod repo update.
* mistyped the name or version.
* not added the source repo that hosts the Podspec to your Podfile.
Note: as of CocoaPods 1.0, pod repo update does not happen on pod install by default.
反正就是你本地的repo里面的某个被别人pod过的类库已经过期或者别人pod的是一个新的版本的，你这里没有
解决方式：
rm -rf ~/.cocoapods/repos/master
pod setup
pod install --verbose --no-repo-update
