release: prepare for release v1.2.9

[brilliant-lx]

Description

Release v1.2.9 is a hard fork release for BSC mainnet.
It sets up the hard fork height for both Plato and Hertz(Berlin,London).

• Plato: fully enable FastFinality at block height: 30,720,096, around Aug-10-2023
• Hertz: several customized EIPs of Berlin&London on BSC, at block height: 31,302,048, around Aug-30-2023

The two hard forks have been running on Testnet for a while and their hard fork height are close, so we decide to put them within a single release to save the upgrade effort.
For the detail changes of the two hard fork, pls refer: https://forum.bnbchain.org/t/bnb-chain-upgrades-mainnet/936

Rationale

v1.2.9

FEATURE

• #1775 upgrade: several hardfork block height on mainnet: Plato, Hertz(Berlin, London)

Example

NA

Changes

This PR setup the hard fork height, the enabled BEPS could bring lots of changes to the ecosystem, include:
After Plato:

• Block Finality: businesses rely on block finality could use the FastFinality feature after Plato

After Hertz:

• New Transaction Types: new types are supported, i.e. "AccessList" & "EIP-1559, but different from Ethereum on BSC"
• Gas Metering: more reasonable gas metering
• new EVM opcode: BaseFee(0x48)
• Reduction in Refunds: SELFDESTRUCT refund will no longer be supported, SSTORE refund will be reduced