Update changelog.

CHANGES.rst

@@ -21,6 +21,10 @@ Bugs fixed
   was fully initialised, thus risking crashes in rare failure cases.
   Original patch by achernomorov.  (Github issue #3215)
 
+* Temporary buffer indexing variables were not released and could show up in
+  C compiler warnings, e.g. in generators.
+  Patch by David Woods.  (Github issues #3430, #3522)
+
 * The compilation cache in ``cython.inline("…")`` failed to take the language
   level into account.
   Patch by will-ca.  (Github issue #3419)