setKotlinVersionInBuildGradle function consumer
Update the kotlin_version variable in root/android/build.gradle file to kotlinVersion.
Implementation
void setKotlinVersionInBuildGradle(String pathToAndroid) {
final buildGradle = pathToAndroid.verifyExists.toBuildGradleFile;
final buildGradleText = buildGradle.readAsStringSync();
buildGradle
..deleteSync()
..createSync()
..writeAsStringSync(buildGradleText.replaceAll(
RegExp("ext.kotlin_version = '.+?'"),
" ext.kotlin_version = '$kotlinVersion'"));
}