re-generate Podfile to fit latest version for XCode, Mac, flutter & CocoaPods#145

cloudwebrtc merged 1 commit intoflutter-webrtc:masterflutter-webrtc/flutter-webrtc-demo:masterfrom

milochen0418:build-issue-144-prmilochen0418/flutter-webrtc-demo:build-issue-144-prCopy head branch name to clipboard