Update release notes wrt #1912

Author: cowtowncoder

release-notes/CREDITS-2.x

@@ -744,3 +744,8 @@ Joe Schafer (jschaf@github)
    (2.9.4)
   * Reported #1907: Remove `getClass()` from `_valueType` argument for error reporting
    (2.9.4)
+
+Deblock Thomas (deblockt@github)
+  * Reported, contributed fix for #1912: `BeanDeserializerModifier.updateBuilder()` does not
+    work to set custom  deserializer on a property (since 2.9.0)
+ (contributed by Deblock T)

release-notes/VERSION-2.x

@@ -9,6 +9,9 @@ Project: jackson-databind
 #1911: Allow serialization of `BigDecimal` as String, using
   `@JsonFormat(shape=Shape.String)`, config overrides
  (suggested by cen1@github)
+#1912: `BeanDeserializerModifier.updateBuilder()` not work to set custom
+  deserializer on a property (since 2.9.0)
+ (contributed by Deblock T)
 
 2.9.4 (24-Jan-2018)