v1.9.0

## What's Changed
* Pangea text update by @vrushankportkey in https://github.com/Portkey-AI/gateway/pull/854
* fix: add verbose mapping for python and js md code blocks by @VisargD in https://github.com/Portkey-AI/gateway/pull/861
* feat: add promptfoo guardrails by @typpo in https://github.com/Portkey-AI/gateway/pull/740
* Fix: promptfoo test cases build errors by @VisargD in https://github.com/Portkey-AI/gateway/pull/863
* fix: handle developer role for google models by @narengogi in https://github.com/Portkey-AI/gateway/pull/865
* Feature: Files and Batches as a unified route by @narengogi in https://github.com/Portkey-AI/gateway/pull/862
* Pangea Plugin updates by @pangea-andrest in https://github.com/Portkey-AI/gateway/pull/871
* #837 delete unsupported fields in gemini models tool definitions by @narengogi in https://github.com/Portkey-AI/gateway/pull/840
* chore: Handle overloaded error in anthropic streaming response by @narengogi in https://github.com/Portkey-AI/gateway/pull/741
* support for gemini thinking model by @narengogi in https://github.com/Portkey-AI/gateway/pull/856
* support milvus db by @narengogi in https://github.com/Portkey-AI/gateway/pull/867
* fix: check for array buffer request body in transformer service by @VisargD in https://github.com/Portkey-AI/gateway/pull/873
* fix logic for total tokens in anthropic stream response by @narengogi in https://github.com/Portkey-AI/gateway/pull/876
* Update Github Readme for LLMs in Prod Report by @siddharthsambharia-portkey in https://github.com/Portkey-AI/gateway/pull/878
* Feat: Mutator Hooks by @VisargD in https://github.com/Portkey-AI/gateway/pull/870
* 1.9.0 by @VisargD in https://github.com/Portkey-AI/gateway/pull/880

## New Contributors
* @typpo made their first contribution in https://github.com/Portkey-AI/gateway/pull/740

**Full Changelog**: https://github.com/Portkey-AI/gateway/compare/v1.8.7...v1.9.0