Add to CHANGELOG.md

CHANGELOG.md

@@ -4,6 +4,21 @@ For advice on how to use these release notes see [our guidance on staying up to
 
 ## Unreleased
 
+### Use our base configurable component to build your own configurable component
+
+We've added a ConfigurableComponent class to help you build your own configurable components. It extends our base component class and so it allows you to focus on your components' specific features by handling these shared behaviours across components:
+
+- checking that GOV.UK Frontend is supported
+- checking that the component is not already initialised on its root element
+- checking the type of the root element and storing it for access within the component as this.$root
+- taking a configuration object as a parameter and then storing it for access within the component as this.config
+- merging a passed configuration object with configuration options specified on the data attributes of the root element
+
+We introduced this change in:
+
+- [#5499: Rename GOVUKFrontendComponentConfigurable, export ConfigurableComponent](https://github.com/alphagov/govuk-frontend/pull/5499)
+- [#5456: Refactor Accordion to extend from a GOVUKFrontendConfigurableComponent](https://github.com/alphagov/govuk-frontend/issues/5456)
+
 ## v5.7.1 (Fix release)
 
 To install this version with npm, run `npm install [email protected]`. You can also find more information about [how to stay up to date](https://frontend.design-system.service.gov.uk/staying-up-to-date/#updating-to-the-latest-version) in our documentation.