Changelog entry for BFT block period transitions (#2955)

Signed-off-by: Jason Frame <jasonwframe@gmail.com>

CHANGELOG.md

@@ -9,6 +9,7 @@
 - Upgrade CircleCI OpenJDK docker image to version 11.0.12. [#2928](https://github.com/hyperledger/besu/pull/2928)
 - Update JDK 11 to latest version in Besu Docker images. [#2925](https://github.com/hyperledger/besu/pull/2925)
 - Add Sepolia proof-of-work testnet configurations [#2920](https://github.com/hyperledger/besu/pull/2920)
+- Allow block period to be configured for IBFT2 and QBFT using transitions [\#2902](https://github.com/hyperledger/besu/pull/2902)
 
 ### Bug Fixes
 - Do not change the sender balance, but set gas fee to zero, when simulating a transaction without enforcing balance checks. [#2454](https://github.com/hyperledger/besu/pull/2454)