docs: add to the CHANGELOG

Author: g-saracca

CHANGELOG.md

@@ -12,11 +12,13 @@ This changelog follows the principles of [Keep a Changelog](https://keepachangel
 - Contact Owner button in File Page.
 - Share button in File Page.
 - Link Collection and Link Dataset features.
+- With the addition of the new runtime configuration approach, we now support dynamic configuration for languages. If more than one language is configured, the Language Switcher will be shown in the header to allow users to change the language.
 
 ### Changed
 
 - Use of the new `sourceLastUpdateTime` query parameter from update dataset and file metadata endpoints to support optimistic concurrency control during editing operations. See [Edit Dataset Metadata](https://guides.dataverse.org/en/6.8/api/native-api.html#edit-dataset-metadata) and [Updating File Metadata](https://guides.dataverse.org/en/6.8/api/native-api.html#updating-file-metadata) guides for more details.
 - Changed the way we were handling DATE type metadata field validation to better match the backend validation and give users better error messages. For example, for an input like “foo AD”, we now show “Production Date is not a valid date. The AD year must be numeric.“. For an input like “99999 AD”, we now show “Production Date is not a valid date. The AD year cant be higher than 9999.“. For an input like “[-9999?], we now show “Production Date is not a valid date. The year in brackets cannot be negative.“, etc.
+- The SPA now fetches the runtime configuration from `config.js` on each load, allowing configurations without rebuilding the app. We don't use `.env` variables at build time anymore.
 
 ### Fixed