Reset CHANGELOG for 2.18.0 release

Signed-off-by: Daniel Widdis <[email protected]>

CHANGELOG.md

@@ -14,16 +14,11 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.1.0/)
 ### Maintenance
 ### Refactoring
 
-## [Unreleased 2.x](https://github.com/opensearch-project/flow-framework/compare/2.14...2.x)
+## [Unreleased 2.x](https://github.com/opensearch-project/flow-framework/compare/2.17...2.x)
 ### Features
-- Adds reprovision API to support updating search pipelines, ingest pipelines index settings ([#804](https://github.com/opensearch-project/flow-framework/pull/804))
-- Adds user level access control based on backend roles ([#838](https://github.com/opensearch-project/flow-framework/pull/838))
-- Support parsing connector_id when creating tools ([#846](https://github.com/opensearch-project/flow-framework/pull/846))
-
 ### Enhancements
 ### Bug Fixes
 ### Infrastructure
 ### Documentation
 ### Maintenance
 ### Refactoring
-- Refactor workflow step resource updates to eliminate duplication ([#796](https://github.com/opensearch-project/flow-framework/pull/796))