Here you can see how the 1.4-M1 stdlib dependency ends up being used:
+--- org.jetbrains.kotlinx:kotlinx-coroutines-core:1.+ -> 1.3.5-2-native-mt-1.4-M1 (*)
+--- org.jetbrains.kotlinx:kotlinx-coroutines-android:1.+ -> 1.3.5-2-native-mt-1.4-M1
| +--- org.jetbrains.kotlin:kotlin-stdlib:1.4-M1 (*)
| \--- org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.5-2-native-mt-1.4-M1 (*)
To solve the problem, please use explicit versions of kotlinx-coroutines-core and kotlinx-coroutines-android dependencies compatible with 1.3.71 Kotlin version (currently 1.3.6: GitHub - Kotlin/kotlinx.coroutines: Library support for Kotlin coroutines).