Update release notes wrt #568

Author: cowtowncoder

Diff for: release-notes/CREDITS-2.x

@@ -377,3 +377,7 @@ Cormac Redmond (@credmond)
  * Reported #535: (avro) AvroSchemaGenerator: logicalType(s) never set for
    non-Date classes
   (2.19.0)
+
+Manuel Sugawara (@sugmanue)
+ * Contributed #568: Improve ASCII decoding performance for `CBORParser`
+  (2.19.0)

Diff for: release-notes/VERSION-2.x

@@ -34,6 +34,8 @@ Active maintainers:
 #539: (avro) Upgrade `org.apache.avro:avro` dependency to 1.11.4
 #547: (all) JSTEP-10: Unify testing structure/tools
  (contributed by Joo-Hyuk K)
+#568: Improve ASCII decoding performance for `CBORParser`
+ (contributed by Manuel S)
 
 2.18.4 (not yet released)