Remove usage of deprecated PreferenceManager

app/src/androidTest/java/com/beemdevelopment/aegis/AegisTestRunner.java

@@ -3,8 +3,8 @@ package com.beemdevelopment.aegis;
 import android.app.Application;
 import android.app.Instrumentation;
 import android.content.Context;
-import android.preference.PreferenceManager;
 
+import androidx.preference.PreferenceManager;
 import androidx.test.core.app.ApplicationProvider;
 import androidx.test.runner.AndroidJUnitRunner;
 

app/src/main/java/com/beemdevelopment/aegis/Preferences.java

@@ -5,9 +5,9 @@ import android.content.SharedPreferences;
 import android.content.res.Resources;
 import android.net.Uri;
 import android.os.Build;
-import android.preference.PreferenceManager;
 
 import androidx.annotation.Nullable;
+import androidx.preference.PreferenceManager;
 
 import com.beemdevelopment.aegis.util.JsonUtils;
 import com.beemdevelopment.aegis.util.TimeUtils;

app/src/test/java/com/beemdevelopment/aegis/PreferencesTest.java

@@ -7,15 +7,13 @@ import static org.junit.Assert.assertTrue;
 
 import android.content.Context;
 import android.content.SharedPreferences;
-import android.os.Build;
-import android.preference.PreferenceManager;
 
+import androidx.preference.PreferenceManager;
 import androidx.test.core.app.ApplicationProvider;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.robolectric.RobolectricTestRunner;
-import org.robolectric.annotation.Config;
 
 import java.util.Date;