Added changelog

Author: sliverc

CHANGELOG.md

@@ -23,6 +23,8 @@ any parts of the framework not mentioned in the documentation should generally b
 * Avoided that an empty attributes dict is rendered in case serializer does not
   provide any attribute fields.
 * Avoided shadowing of exception when rendering errors (regression since 4.3.0).
+* Ensured that sparse fields only applies when rendering, not when parsing.
+* Adjusted that sparse fields properly removes meta fields when not defined.
 
 ### Removed