Update NEWS for null deprecation bug fix

Author: Girgias

NEWS

@@ -6,6 +6,8 @@ PHP NEWS
  . Fixed bug GH-20270 (Broken parent hook call with named arguments). (ilutov)
  . Fixed bug GH-20183 (Stale EG(opline_before_exception) pointer through eval).
  (ilutov)
+ . Fixed bug GH-20194 (null offset deprecation not emitted for writes).
+ (Girgias)
 
 - Opcache:
  . Fixed bug GH-20012 (heap buffer overflow in jit). (Arnaud)