message: Update packages/target-ethers-v5/README.md
  BigNumber moved from ethers/utils to ethers
diff: @@ -45,7 +45,7 @@ Abstract contracts or solidity interfaces are handled a bit different, because t
  Suppose you have an `Erc20Token.sol` solidity interface and a `DummyToken.sol` contract implementing it.
  ```typescript
  -import { BigNumber } from 'ethers/utils';
  +import { BigNumber } from 'ethers';
  import { Wallet } from 'ethers';
  import { DummyTokenFactory } from 'typechain-out-dir/DummyTokenFactory';
  