Update CHANGELOG for 2.5.0 (#2248)

* Update CHANGELOG for 2.5.0
* Include librdkafka 2.5.0 in changelog

---------

Co-authored-by: Anchit Jain <[email protected]>

Author: rayokota

CHANGELOG.md

@@ -1,5 +1,14 @@
 # 2.5.0
 
+## Enhancements
+
+- References librdkafka.redist 2.5.0. Refer to the [librdkafka v2.5.0 release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.5.0) for more information.
+- Add support for metadata and ruleSet in the schema registry client, which together support data 
+contracts.
+- Add support for CSFLE (client-side field-level encryption) for AWS, Azure, GCP, and HashiCorp 
+Vault.  See the encryption examples in the examples directory.
+- Add support for CEL, CEL_FIELD, and JSONata rules.
+
 ## Fixes
 
 - Switch license expression and other repo information. (#2192, @thompson-tomo)