Fix crash on Edit Tags dialog

Observed on release variants with crash log
msg: java.lang.NoSuchFieldException: Failed to set TextInputLayout hint (collapsed) color: null
stacktrace: io.reactivex.exceptions.CompositeException: 1 exceptions occurred. 
	at io.reactivex.internal.observers.LambdaObserver.a(SourceFile:15)
	at io.reactivex.internal.observers.LambdaObserver.a(SourceFile:10)
	at io.reactivex.internal.operators.observable.ObservableDistinctUntilChanged$DistinctUntilChangedObserver.a(SourceFile:10)
	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.e(SourceFile:8)
	at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.run(SourceFile:3)
	at io.reactivex.android.schedulers.HandlerScheduler$ScheduledRunnable.run(SourceFile:1)
	at android.os.Handler.handleCallback(Handler.java:873)
	at android.os.Handler.dispatchMessage(Handler.java:99)
	at android.os.Looper.loop(Looper.java:193)
	at android.app.ActivityThread.main(ActivityThread.java:6672)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:495)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:860)

Author: GeoZac

app/proguard-rules.pro

@@ -113,4 +113,7 @@
 
 # Custom Cast Media Button, only referenced via menu
 -keep class com.simplecity.amp_library.ui.views.CustomMediaRouteActionProvider.CustomMediaRouteButton { *; }
--keep class com.simplecity.amp_library.ui.views.CustomMediaRouteActionProvider { *; }
+-keep class com.simplecity.amp_library.ui.views.CustomMediaRouteActionProvider { *; }
+
+# Adopted from https://github.com/afollestad/aesthetic/issues/41
+-keep class com.google.android.material.textfield.** { *; }