Update CHANGELOG for v1.4.3 (#5775)

## Motivation

Prepares release for v1.4.3

CHANGELOG.md

@@ -2,18 +2,21 @@
 
 See [RELEASE](./RELEASE.md) for workflow instructions.
 
-## UNRELEASED
+## Release v1.4.3
 
-### Upgrade information
+### Improvements
 
-### Highlights
+* [#5753](https://github.com/spacemeshos/go-spacemesh/pull/5753) Fix for a possible segmentation fault in setups with
+  remote post services when an identity does their initial proof.
 
-### Features
+* [#5755](https://github.com/spacemeshos/go-spacemesh/pull/5755) improve efficiency of downloading and applying blocks
+  after ballots were counted.
 
-### Improvements
+* [#5761](https://github.com/spacemeshos/go-spacemesh/pull/5761) don't interrupt sync if ballots in a layer were
+  ignored or rejected.
 
-* [#5753](ttps://github.com/spacemeshos/go-spacemesh/pull/5753) Fix for a possible segmentation fault in setups with
-  remote post services when an identity does their initial proof.
+* [#5762](https://github.com/spacemeshos/go-spacemesh/pull/5762) Fix a bug where the node could get stuck in a loop
+  when trying to fetch a block that is not in the mesh.
 
 ## Release v1.4.2