chore: Update CHANGELOG for release 2.4.0

Signed-off-by: Ondrej Fabry <[email protected]>

CHANGELOG.md

@@ -4,8 +4,8 @@
 
 ## Release Notes
 
+- [v2.4.0](#v2.4.0)
 - [v2.3.0](#v2.3.0)
-  - [v2.3.1](#v2.3.1)
 - [v2.2.0](#v2.2.0)
 - [v2.2.0-beta](#v2.2.0-beta)
 - [v2.1.0](#v2.1.0)
@@ -47,16 +47,16 @@ RELEASE CHANGELOG TEMPLATE:
 ### Documentation
 -->
 
-<a name="v2.3.1"></a>
-# [2.3.1](https://github.com/ligato/vpp-agent/compare/v2.3.0...v2.3.1) (2019-10-18)
+<a name="v2.4.0"></a>
+# [2.3.1](https://github.com/ligato/vpp-agent/compare/v2.3.0...v2.4.0) (2019-10-21)
 - **VPP 20.01-379** (`20.01-rc0~379-ga6b93eac5`)
 - **VPP 20.01-324** (`20.01-rc0~324-g66a332cf1`)
 - **VPP 19.08.1** (default)
 - **VPP 19.04** (backward compatible)
 - cn-infra v2.2
 
 ### New Features
-This minor release introduces compatibility with two different commits of the VPP 20.01. Previously compatible version was updated to commit `324-g66a332cf1`, and support for `379-ga6b93eac5` was added. Other previous versions remained.
+This release introduces compatibility with two different commits of the VPP 20.01. Previously compatible version was updated to commit `324-g66a332cf1`, and support for `379-ga6b93eac5` was added. Other previous versions remained.
 * [Telemetry][vpp-telemetry]
   - Added `StatsPoller` service periodically retrieving VPP stats.