Fixed CHANGELOG.md due to duplicate beta.13 sections (#4717)

Author: heath-freenome

CHANGELOG.md

@@ -32,11 +32,6 @@ should change the heading of the (upcoming) version to include a major version b
 - Extended `Registry` interface to include optional `experimental_componentUpdateStrategy` property
 - Added `shallowEquals()` utility function for shallow equality comparisons
 - Fixed boolean fields incorrectly set to `{}` when switching oneOf/anyOf options with `mergeDefaultsIntoFormData` set to `useDefaultIfFormDataUndefined`, fixing [#4709](https://github.com/rjsf-team/react-jsonschema-form/issues/4709) ([#4710](https://github.com/rjsf-team/react-jsonschema-form/pull/4710))
-
-# 6.0.0-beta.13
-
-## rjsf/utils
-
 - Always make all references absolute in nested bundled schemas
 
 # 6.0.0-beta.12