[!] Oh no, an error occurred.

Search for existing GitHub issues similar to yours:
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Looking for related issues on cocoapods/cocoapods...
/Users/XXX/.rvm/gems/ruby-2.7.0/gems/cocoapods-1.8.0/lib/cocoapods/user_interface/inspector_reporter.rb:80: warning: URI.escape is obsolete
 - RuntimeError - [Xcodeproj] Unknown object version.
   https://github.com/CocoaPods/CocoaPods/issues/10984 [closed] [13 comments]
   4 days ago

/Users/XXX/.rvm/gems/ruby-2.7.0/gems/cocoapods-1.8.0/lib/cocoapods/user_interface/inspector_reporter.rb:80: warning: URI.escape is obsolete
 - Unknown object version
   https://github.com/CocoaPods/CocoaPods/issues/10973 [closed] [10 comments]
   6 weeks ago

/Users/XXX/.rvm/gems/ruby-2.7.0/gems/cocoapods-1.8.0/lib/cocoapods/user_interface/inspector_reporter.rb:80: warning: URI.escape is obsolete
 - RuntimeError - [Xcodeproj] Unknown object version.
   https://github.com/CocoaPods/CocoaPods/issues/7458 [closed] [21 comments]
   5 weeks ago

and 71 more at:
https://github.com/cocoapods/cocoapods/search?q=%5BXcodeproj%5D%20Unknown%20object%20version.&type=Issues&utf8=✓

原因：Pod版本与Xcode版本不兼容，按顺序执行下面执行即可。

sudo gem update --system
sudo gem install -n /usr/local/bin cocoapods