Update changelog (#5529)

Author: tamirms

services/horizon/CHANGELOG.md

@@ -9,6 +9,9 @@ file. This project adheres to [Semantic Versioning](http://semver.org/).
 - Fix the issue where the skip-txmeta flag is not being applied in `/transactions/{tx-id}` endpoint ([5523](https://github.com/stellar/go/pull/5523)).
 - Fix `horizon_ingest_reap_lookup_tables_duration_seconds` metric which reports the total number of lookup table rows which were reaped ([5528](https://github.com/stellar/go/pull/5528)).
 
+### Removed
+- Removed defunct `init-genesis-state` command ([5504](https://github.com/stellar/go/pull/5504)).
+
 ## 22.0.0-rc2