Your error itself gave you the solution. You need to upgrade kotlin-stdlib-jdk7 dependencies version in this line.

implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"

Find where $kotlin_version is defined. Change it to latest version as defined on Official Kotlin Release page

• What went wrong:
  The Android Gradle plugin supports only Kotlin Gradle plugin version 1.3.10 and higher.
  The following dependencies do not satisfy the required version:
  project ‘:drawerbehavior’ -> org.jetbrains.kotlin:kotlin-gradle-plugin:1.2.71

• Try:
  Run with –stacktrace option to get the stack trace. Run with –info or –debug option to get more log output. Run with –scan to get full insights.

• Get more help at https://help.gradle.org

BUILD FAILED in 4s
Running Gradle task ‘assembleRelease’…
Running Gradle task ‘assembleRelease’… Done 5.3s
Gradle task assembleRelease failed with exit code 1

android {
compileSdkVersion 28

sourceSets {
    main.java.srcDirs += 'src/main/kotlin'
}

lintOptions {
    disable 'InvalidPackage'
}

defaultConfig {
    // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
    applicationId "com.example.sununigeriaflutter"
    minSdkVersion 16
    targetSdkVersion 28
    versionCode flutterVersionCode.toInteger()
    versionName flutterVersionName
    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}

buildTypes {
    release {
        // TODO: Add your own signing config for the release build.
        // Signing with the debug keys for now, so `flutter run --release` works.
        signingConfig signingConfigs.debug
    }
}

}

flutter {
source ‘../..’
}

dependencies {
implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test:runner:1.2.0'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

}