Add new features to changes.md (#37308)

Author: tarun-google

CHANGES.md

@@ -103,6 +103,8 @@
 
 * Support configuring Firestore database on ReadFn transforms (Java) ([#36904](https://github.com/apache/beam/issues/36904)).
 * (Python) Inference args are now allowed in most model handlers, except where they are explicitly/intentionally disallowed ([#37093](https://github.com/apache/beam/issues/37093)).
+* (Python) Add support for EnvoyRateLimiter, to allow rate limiting in DoFns ([#37135](https://github.com/apache/beam/pull/37135)).
+* (Python) Add support for RateLimiting in Remote Model Handler ([#37218](https://github.com/apache/beam/pull/37218)).
 
 ## Bugfixes