Update release notes wrt #2978

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -816,6 +816,8 @@ Carter Kozak (carterkozak@github)
    (2.12.0)
   * Contributed #2931: Add errorprone static analysis profile to detect bugs at build time
    (2.12.0)
+  * Contributed #2978: Fix failing `double` JsonCreators in jackson 2.12.0
+   (2.12.1)
 
 Reinhard Prechtl (dnno@github)
   * Reported #2034: Serialization problem with type specialization of nested generic types

release-notes/VERSION-2.x

@@ -13,6 +13,8 @@ Project: jackson-databind
  (reported by andpal@github)
 #2973: DeserializationProblemHandler is not invoked when trying to deserializing String
  (reported by zigzago@github)
+#2978: Fix failing `double` JsonCreators in jackson 2.12.0
+ (contributed by Carter K)
 
 2.12.0 (29-Nov-2020)