Changelog: list template breaking changes

semantic-conventions/CHANGELOG.md

@@ -4,8 +4,9 @@ Please update the changelog as part of any significant pull request.
 
 ## Unreleased
 
-- BREAKING: Attribute property `required` is removed and replaced by `requirement_level`
-  ([#92](https://github.com/open-telemetry/build-tools/pull/92)).
+- BREAKING: Introduced attribute requirement levels ([#92](https://github.com/open-telemetry/build-tools/pull/92)):
+  - Schema: Attribute property `required` is removed and replaced by `requirement_level`, supported values are changed to `required` (previously `always`), `conditionally_required` (previously `conditional`), `recommended`, and `optional`.
+  - Templates: `opentelemetry.semconv.model.semantic_attribute.Required` enum is renamed to `RequirementLevel`, `required_msg` is renamed to `requirement_level_msg`
 
 ## v0.8.0