Update CHANGELOG.md to mention new p2p flood publish param (#8633)

Co-authored-by: Gabriel Fukushima <gabrielfukushima@gmail.com>

CHANGELOG.md

@@ -15,6 +15,7 @@
 - Added support for [Ephemery Testnet](https://github.com/ephemery.dev) `--network=ephemery`
 - Renamed metrics `validator_attestation_publication_delay`,`validator_block_publication_delay` and `beacon_block_import_delay_counter` to include the suffix `_total` added by the current version of prometheus.
 - Updated bootnodes for Holesky network
+- Added new `--p2p-flood-publish-enabled` parameter to control whenever flood publishing behaviour is enabled (applies to all subnets). Previous teku versions always had this behaviour enabled. Default is `true`.
 
 ### Bug Fixes
  - removed a warning from logs about non blinded blocks being requested (#8562)