Tests: migrating to mtgjson v5 (#6808);

Mage.Verify/src/main/java/mage/verify/mtgjson/MtgJsonSet.java

@@ -0,0 +1,15 @@
+package mage.verify.mtgjson;
+
+import java.util.List;
+
+public final class MtgJsonSet {
+    // v5 support
+    // https://mtgjson.com/data-models/card-atomic/
+    // contains only used fields, if you need more for tests then just add it here
+
+    public List<MtgJsonCard> cards;
+    public String code;
+    public String name;
+    public String releaseDate;
+    public int totalSetSize;
+}