chore: update changelog to include notes about GraphQL API change

Signed-off-by: Spencer Norman <[email protected]>

Author: spencern

CHANGELOG.md

@@ -1,10 +1,13 @@
 # v2.0.0-rc.12
-We have [renamed](https://github.com/reactioncommerce/example-storefront/pull/544) this project from `reaction-next-starterkit` to `example-storefront` to better convey the intent behind our creating it.  We’re also [updating our docs](https://github.com/reactioncommerce/reaction-docs/pull/829) to clarify this change.
-
 This is our fourth release candidate for this project. While this project is technically still `pre-release` until we've released the final 2.0.0 version, it's the most stable version of Reaction Commerce, and we recommend starting new projects with it at this point. See https://github.com/reactioncommerce/example-storefront/issues/487#issuecomment-507468894 for more detail on this.
 
 This version should be used with `v2.0.0-rc.12` of https://github.com/reactioncommerce/reaction
 
+## Highlights
+We have [renamed](https://github.com/reactioncommerce/example-storefront/pull/544) this project from `reaction-next-starterkit` to `example-storefront` to better convey the intent behind our creating it.  We’re also [updating our docs](https://github.com/reactioncommerce/reaction-docs/pull/829) to clarify this change.
+
+The GraphQL API in [reaction v2.0.0-rc.12](https://github.com/reactioncommerce/reaction/pull/5259) has been changed from `/graphql-alpha` to `graphql-beta` to indicate the increased stability of the API. We think there are still some breaking changes to come in the next 3-6 months to the GraphQL API which is why we're keeping the `-beta` suffix for now. As you find bugs with that API, please file issues in the [reaction](https://github.com/reactioncommerce/reaction/issues) repo.
+
 # Improvements
 
 ## Feature