sample env improvement

[Afjal12]

THROTTLE_PER_FIVE_MINS = '' # Optional
JSON_RPC_PROVIDER_{CHAIN ID} = { RPC Provider}

RPC Providers must be set for the following CHAIN IDs:

MAINNET = 1

ROPSTEN = 3

RINKEBY = 4

GOERLI = 5

KOVAN = 42

OPTIMISM = 10

OPTIMISTIC_KOVAN = 69

ARBITRUM_ONE = 42161

ARBITRUM_RINKEBY = 421611

POLYGON = 137

POLYGON_MUMBAI = 80001

BNB = 56

TENDERLY_USER = '' # For enabling Tenderly simulations
TENDERLY_PROJECT = '' # For enabling Tenderly simulations
TENDERLY_ACCESS_KEY = '' # For enabling Tenderly simulations

I have set the rpc url but its throw internal server error, Can you please update a required field in sample env file for better understanding.

Thanks.