[J21] added set

Mage.Client/src/main/java/org/mage/plugins/card/dl/sources/ScryfallImageSupportCards.java

@@ -505,6 +505,7 @@ public class ScryfallImageSupportCards {
             add("H1R"); // Modern Horizons 1 Timeshifts
             add("AFR"); // Adventures in the Forgotten Realms
             add("AFC"); // Forgotten Realms Commander
+            add("J21"); // Jumpstart: Historic Horizons
             add("MID"); // Innistrad, Midnight Hunt
         }
     };