Remove out of date repositories jcenter()

[kaitotokyo]

File :
https://github.com/qonversion/flutter-sdk/blob/develop/android/build.gradle

 repositories {
        google()
        mavenCentral()
        jcenter()
    }

rootProject.allprojects {
    repositories {
        google()
        mavenCentral()
        jcenter()
        mavenLocal()
    }
}

JCenter artifact repository used by many Android projects, made JCenter a read-only repository on March 31, 2021.
https://developer.android.com/build/jcenter-migration

Please remove the jcenter()

[SpertsyanKM]

Hello! We appreciate your report! We will consider it for future releases.