Fix Flutter 1.7 upgrade issues

After upgrade to flutter 1.7 by using "flutter upgrade" you may have some issue with the cache issue, as new Flutter version change the way of buil the XCode project. Please try one of following solutions to clean cache and update the Pod libraries:


SOLUTION 1:
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1. Clean up Flutter cache: 
$ flutter clean

2. Go to ios folder: 
$ sudo gem install cocoapods-deintegrate cocoapods-clean
$ pod deintegrate
$ pod clean

3. Go to the project folder:
$ flutter run  


SOLUTION 2:
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1. Open XCode: File > Workspace Settings... > Build System, change dropdown to New Build System (Default):

2. To to ios folder, to update latest cocoapod:
$ pod update

3. Go to project folder and make sure all there is no issues by running:
$ flutter doctor
$ flutter run