fix: work around default-exporting json module

See webpack/webpack#13469

Author: legobeat

src/index.js

@@ -9,7 +9,8 @@ import {
 } from 'eth-sig-util';
 import { ethers } from 'ethers';
 import { toChecksumAddress } from 'ethereumjs-util';
-import {
+import Constants from './constants.json';
+const {
   hstBytecode,
   hstAbi,
   piggybankBytecode,
@@ -22,7 +23,7 @@ import {
   multisigBytecode,
   erc1155Abi,
   erc1155Bytecode,
-} from './constants.json';
+} = Constants;
 
 let ethersProvider;
 let hstFactory;