message: refactor(core): deprecate hdPath in src/bitgo.ts
  Issue:
diff: import * as superagent from 'superagent';
  import * as bitcoin from '@bitgo/utxo-lib';
  -import { makeRandomKey, hdPath } from './bitcoin';
  +import { makeRandomKey } from './bitcoin';
  import * as secp256k1 from 'secp256k1';
  import bitcoinMessage = require('bitcoinjs-message');
  import { BaseCoin } from './v2/baseCoin';
  @@ -45,6 +45,7 @@ import {
  toBitgoRequest,
  verifyResponse,
  } from './api';
  +import { sanitizeLegacyPath } from './bip32path';
  const debug = debugLib('bitgo:index');
  @@ -1045,8 +1046,8 @@ export class BitGo {
  // BIP32 derivation path is applied to both client and server master keys
  const derivationPath = responseBody.derivationPath;
  - const clientDerivedNode = hdPath(clientHDNode).derive(derivationPath);
  - const serverDerivedNode = hdPath(serverHDNode).derive(derivationPath);
  + const clientDerivedNode = clientHDNode.derivePath(sanitizeLegacyPath(derivationPath));
  + const serverDerivedNode = serverHDNode.derivePath(sanitizeLegacyPath(derivationPath));
  const publicKey = serverDerivedNode.keyPair.getPublicKeyBuffer();
  const secretKey = clientDerivedNode.keyPair.d.toBuffer(32);
  