Add artwork to album attributes

src/main/kotlin/com/stevesoltys/applemusic/model/Artwork.kt

@@ -0,0 +1,23 @@
+package com.stevesoltys.applemusic.model
+
+/**
+ * @author Steve Soltys
+ */
+class Artwork {
+
+    var bgColor: String? = null
+
+    var height: Int? = null
+
+    var width: Int? = null
+
+    var textColor1: String? = null
+
+    var textColor2: String? = null
+
+    var textColor3: String? = null
+
+    var textColor4: String? = null
+
+    var url: String? = null
+}

src/main/kotlin/com/stevesoltys/applemusic/model/album/AlbumAttributes.kt

@@ -1,6 +1,7 @@
 package com.stevesoltys.applemusic.model.album
 
 import com.fasterxml.jackson.annotation.JsonProperty
+import com.stevesoltys.applemusic.model.Artwork
 
 /**
  * @author Steve Soltys
@@ -20,6 +21,8 @@ class AlbumAttributes {
 
     var genreNames: Array<String>? = null
 
+    var artwork: Artwork? = null
+
     @JsonProperty("isComplete")
     var complete: Boolean? = null