Update to kotlinx.coroutines 0.30.2

Almost done, honest!

app/build.gradle

@@ -228,7 +228,7 @@ dependencies {
 
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 
-    final coroutines_version = '0.26.0'
+    final coroutines_version = '0.30.2'
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutines_version"
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core-common:$coroutines_version" // TODO: hack!
     implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:$coroutines_version"