message: feat: use lodash assign
diff: +import _ from 'lodash';
  +
  import { StacksTransaction } from './transaction';
  import { StacksNetwork, StacksMainnet, StacksTestnet } from '@stacks/network';
  @@ -185,7 +187,7 @@ export async function broadcastRawTransaction(
  };
  if (attachment) {
  - options = Object.assign(options, {
  + options = _.assign(options, {
  headers: {
  'Content-Type': 'application/json',
  },
  @@ -195,7 +197,7 @@ export async function broadcastRawTransaction(
  })
  })
  } else {
  - options = Object.assign(options, {
  + options = _.assign(options, {
  headers: {
  'Content-Type': 'application/octet-stream',
  },
  