Update release notes wrt #990

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -26,6 +26,8 @@ No changes since 2.14
   padding character
  (reported by @Vity01)
 #967: Address performance issue with `BigDecimalParser`
+#987: Backport removal of BigDecimal to BigInt conversion (#987)
+ (contributed by @pjfanning)
 
 2.14.2 (28-Jan-2023)