title: Jackson error when enable proguard (minify)
body: <p>I use implementation <code>'com.fasterxml.jackson.core:jackson-databind:2.9.8'</code> and when i enable minify i get this errors </p>
  
  <pre><code>2019-06-27 20:23:11.172 28675-29539/? W/System.err: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: No serializer found for class com.example.tst.a.b.b and no properties discovered to create BeanSerializer (to avoid exception, disable SerializationFeature.FAIL_ON_EMPTY_BEANS)
  2019-06-27 20:23:11.172 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.SerializerProvider.reportBadDefinition(SerializerProvider.java:1191)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:313)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:71)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:33)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider._serialize(DefaultSerializerProvider.java:480)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.ser.DefaultSerializerProvider.serializeValue(DefaultSerializerProvider.java:319)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.ObjectMapper._configAndWriteValue(ObjectMapper.java:3905)
  2019-06-27 20:23:11.173 28675-29539/? W/System.err:     at com.fasterxml.jackson.databind.ObjectMapper.writeValueAsString(ObjectMapper.java:3219)
  </code></pre>
  
  <p>this is what i add ProGuard rules but it doesn't fix my problem </p>
  
  <pre><code>-keepattributes *Annotation*,EnclosingMethod,Signature
  -keep class com.fasterxml.** { *; }
  -keepclassmembers class ** extends com.fasterxml.jackson.databind.ser.std.** {
     public &lt;init&gt;(...);
  }
  
  -keepclassmembers class ** extends com.fasterxml.jackson.databind.deser.std.** {
     public &lt;init&gt;(...);
  }
  -keepattributes *Annotation*,EnclosingMethod,Signature
   -keepnames class com.fasterxml.jackson.** { *; }
   -dontwarn com.fasterxml.jackson.databind.**
   -keep class org.codehaus.** { *; }
   -keepclassmembers public final enum org.codehaus.jackson.annotate.JsonAutoDetect$Visibility {
       public static final org.codehaus.jackson.annotate.JsonAutoDetect$Visibility *; }
  -keep public class your.class.** {
      *;
  }
  -dontwarn com.fasterxml.jackson.databind.
  </code></pre>