Add changelog entry for unit_reset() fix

Author: df7cb

debian/changelog

@@ -2,6 +2,8 @@ postgresql-unit (3.2) UNRELEASED; urgency=medium
 
   * Support exponents written using Unicode superscript characters.
   * Report 22P02/invalid_text_representation on invalid unit input.
+  * Fix crash when unit_reset() runs into an OOM error. Patch by Andreas
+    Seltenreich, thanks!
 
  -- Christoph Berg <[email protected]>  Sat, 08 Apr 2017 18:36:50 +0200