message: refactor(core): use bip32 in keychains
  Issue:
diff: // Copyright 2014, BitGo, Inc. All Rights Reserved.
  //
  +import * as bip32 from 'bip32';
  import { randomBytes } from 'crypto';
  import * as common from './common';
  import { Util } from './v2/internal/util';
  -import * as bitcoin from '@bitgo/utxo-lib';
  const _ = require('lodash');
  let ethereumUtil;
  import * as Bluebird from 'bluebird';
  @@ -55,9 +55,9 @@ Keychains.prototype.isValid = function (params) {
  try {
  if (!params.key.path) {
  - bitcoin.HDNode.fromBase58(params.key);
  + bip32.fromBase58(params.key);
  } else {
  - bitcoin.HDNode.fromBase58(params.key.xpub).derivePath(sanitizeLegacyPath(params.key.path));
  + bip32.fromBase58(params.key.xpub).derivePath(sanitizeLegacyPath(params.key.path));
  }
  return true;
  } catch (e) {
  @@ -86,7 +86,7 @@ Keychains.prototype.create = function (params) {
  seed = params.seed;
  }
  - const extendedKey = bitcoin.HDNode.fromSeedBuffer(seed);
  + const extendedKey = bip32.fromSeed(seed);
  const xpub = extendedKey.neutered().toBase58();
  let ethAddress;
  @@ -128,7 +128,7 @@ Keychains.prototype.deriveLocal = function (params) {
  let hdNode;
  try {
  - hdNode = bitcoin.HDNode.fromBase58(params.xprv || params.xpub);
  + hdNode = bip32.fromBase58(params.xprv || params.xpub);
  } catch (e) {
  throw apiResponse(400, {}, 'Unable to parse the xprv or xpub');
  }
  