Automatically assigning platform `iOS` with version `10.0` on target `Runner` because no platform was specified - Flutter

If you had this error when trying to build Flutter app on iPhone 12 Pro Max this is the solution that worked for me:

• Go in the flutter_project/ios, open the Runner.xcodeproj, and change the iOS version to 10.0, in the Deployment Info, if you have version that is bellow.

• In your terminal in flutter_project run

$ flutter clean

• In your terminal in flutter_project/ios run the commands

$ pod update
$ pod repo update

• Open iOS simulator and in terminal run

$ flutter run

And the problem is solved!