Fix #1343 block_suggestion response does not support description in an option (#1351)

Author: seratch

slack-app-backend/src/main/java/com/slack/api/app_backend/interactive_components/response/Option.java

@@ -13,4 +13,10 @@
 public class Option {
     private TextObject text;
     private String value;
+    private TextObject description;
+
+    // For backward-compatibility
+    public Option(TextObject text, String value) {
+        this(text, value, null);
+    }
 }