From flutter v2.8
1. Inside local.properties add
sdk.dir='<path>'
flutter.sdk='<path>'
flutter.buildMode=debug
flutter.versionName=1.0.0
flutter.versionCode=1
flutter.minSdkVersion=21
flutter.targetSdkVersion=30
flutter.compileSdkVersion=30
2. Then inside app/build.gradle update to below code
defaultConfig {
minSdkVersion localProperties.getProperty('flutter.minSdkVersion').toInteger()
targetSdkVersion localProperties.getProperty('flutter.targetSdkVersion').toInteger()
versionCode flutterVersionCode.toInteger()
versionName flutterVersionName
}