How to create podfile in codemagic?

I'm trying to build an iOS flutter app in windows using Codemagic. I created the flutter project in android studio and uploaded it to github in order to use it in Codemagic... But when I try to build the iOS app, Codemagic throws me this error:

Warning: Building for device with codesigning disabled. You will have to manually codesign before deploying to device.
Building com.jmmago.saltApp for device (ios-release)...
Running pod install...                                             16.0s
Running Xcode build...                                          
Xcode build done.                                           124.3s
Failed to build iOS app
Error output from Xcode build:
↳
    ** BUILD FAILED **


Xcode's output:
↳
    /Users/builder/programs/flutter/.pub-cache/hosted/pub.dartlang.org/barcode_scan-3.0.1/ios/Classes/protos/protos.pb.swift:14:8: error: compiling for iOS 8.0, but module 'SwiftProtobuf' has a minimum deployment target of iOS 9.0: /Users/builder/clone/build/ios/Release-iphoneos/SwiftProtobuf/SwiftProtobuf.framework/Modules/SwiftProtobuf.swiftmodule/armv7-apple-ios.swiftmodule
    import SwiftProtobuf
           ^
    Command CompileSwift failed with a nonzero exit code
    note: Using new build system
    note: Building targets in parallel
    note: Planning build
    note: Constructing build description
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'barcode_scan' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'sqflite' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'shared_preferences' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'path_provider' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'image_picker' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'MTBBarcodeScanner' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'FMDB' from project 'Pods')
    warning: The iOS deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.1.99. (in target 'Flutter' from project 'Pods')

════════════════════════════════════════════════════════════════════════════════
Building a deployable iOS app requires a selected Development Team with a 
Provisioning Profile. Please ensure that a Development Team is selected by:
  1- Open the Flutter project's Xcode target with
       open ios/Runner.xcworkspace
  2- Select the 'Runner' project in the navigator then the 'Runner' target
     in the project settings
  3- Make sure a 'Development Team' is selected. 
     - For Xcode 10, look under General > Signing > Team.
     - For Xcode 11 and newer, look under Signing & Capabilities > Team.
     You may need to:
         - Log in with your Apple ID in Xcode first
         - Ensure you have a valid unique Bundle ID
         - Register your device with your Apple Developer Account
         - Let Xcode automatically provision a profile for your app
  4- Build or run your project again

For more information, please visit:
  https://flutter.dev/setup/#deploy-to-ios-devices

Or run on an iOS simulator without code signing
════════════════════════════════════════════════════════════════════════════════
Encountered error while building for device.


Build failed :|
Failed to build for iOS

In this question, they solved this same problem creating a podfile. But how I create a Podfile? I have to create it in my project and then push it to github? Or there is a way to create it in Codemagic?