Bump send and browser-sync in /guide

Bumps [send](https://github.com/pillarjs/send) and [browser-sync](https://github.com/BrowserSync/browser-sync). These dependencies needed to be updated together.

Updates `send` from 0.16.2 to 0.19.1
- [Release notes](https://github.com/pillarjs/send/releases)
- [Changelog](https://github.com/pillarjs/send/blob/master/HISTORY.md)
- [Commits](https://github.com/pillarjs/send/commits)

Updates `browser-sync` from 3.0.2 to 3.0.3
- [Release notes](https://github.com/BrowserSync/browser-sync/releases)
- [Changelog](https://github.com/BrowserSync/browser-sync/blob/master/changelog.js)
- [Commits](BrowserSync/browser-sync@v3.0.2...v3.0.3)

---
updated-dependencies:
- dependency-name: send
  dependency-type: indirect
- dependency-name: browser-sync
  dependency-type: indirect
...

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