post https://eth-mainnet.alchemyapi.io/v2/
Returns a fee per gas that is an estimate of how much you can pay as a priority fee, or 'tip', to get a transaction included in the current block.
Generally you will use the value returned from this method to set the maxFeePerGas
in a subsequent transaction that you are submitting. This method was introduced with EIP 1559.
**NOTE: **This method is not currently supported on Kovan