Update changelog

CHANGELOG.rst

 ChangeLog
 =========
 
+Unreleased
+----------
+
+* Add method `blacklisted_by` to get set of identifiers of domain name blocks
+
+
 9.0.0 (2023-11-29)
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@@ -12,6 +18,7 @@ ChangeLog
 
 * Add method is_registered_by_uuid and is_registered_by_history_uuid as a workaround until Info vs Update clash is fixed
 
+
 8.0.0 (2023-09-25)
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