message: refactor(core): use bip32 in src/wallet.ts
  Issue:
diff: import { Codes, VirtualSizes } from '@bitgo/unspents';
  +import * as bip32 from 'bip32';
  const TransactionBuilder = require('./transactionBuilder');
  import * as bitcoin from '@bitgo/utxo-lib';
  const PendingApproval = require('./pendingapproval');
  @@ -289,9 +290,9 @@ Wallet.prototype.generateAddress = function ({ segwit, path, keychains, threshol
  const network = common.Environments[this.bitgo.getEnv()].network;
  const derivedKeys = rootKeys.map(function (k) {
  - const hdnode = bitcoin.HDNode.fromBase58(k.xpub);
  + const hdnode = bip32.fromBase58(k.xpub);
  const derivationPath = k.path + (k.walletSubPath || '') + path;
  - return hdnode.derivePath(sanitizeLegacyPath(derivationPath)).getPublicKeyBuffer();
  + return hdnode.derivePath(sanitizeLegacyPath(derivationPath)).publicKey;
  });
  const pathComponents = path.split('/');
  @@ -1724,7 +1725,7 @@ Wallet.prototype.getAndPrepareSigningKeychain = function (params, callback) {
  // Caller provided an xprv - validate and construct keychain object
  let xpub;
  try {
  - xpub = bitcoin.HDNode.fromBase58(params.xprv).neutered().toBase58();
  + xpub = bip32.fromBase58(params.xprv).neutered().toBase58();
  } catch (e) {
  throw new Error('Unable to parse the xprv');
  }
  