Bump org.jetbrains.kotlin:kotlin-gradle-plugin from 2.0.20 to 2.1.0 in /android/flutter_plugins/qrscanner_zxing/android

Bump org.jetbrains.kotlin:kotlin-gradle-plugin from 2.0.20 to 2.1.0 in /android/flutter_plugins/qrscanner_zxing/android #3246