* added eth_maxPriorityFeePerGas rpc call
* cargo fmt
* moved block_base_fee implementation into the trait
* added basic test for eth_maxPriorityFeePerGas
* added test for eth_maxPriorityFeePerGas calculation
* Added support for zero-cost transactions
* Added 'eip1559_not_activated' error
* Fixes 'chain::supplier::test::return_nodes' test
* cargo fmt
* cargo fmt
* made calculation of fallback priority fee to ignore zero-cost transactions
* cargo fmt
* made use of 'saturating_sub' instead of minus
Rim Rakhimov
Adria Massanet