[Security] Bump node-fetch from 2.6.0 to 2.6.1

Bumps [node-fetch](https://github.com/bitinn/node-fetch) from 2.6.0 to 2.6.1. **This update includes a security fix.**
- [Release notes](https://github.com/bitinn/node-fetch/releases)
- [Changelog](https://github.com/node-fetch/node-fetch/blob/master/docs/CHANGELOG.md)
- [Commits](node-fetch/node-fetch@v2.6.0...v2.6.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>