[Security] Bump acorn from 7.1.0 to 7.1.1

Bumps [acorn](https://github.com/acornjs/acorn) from 7.1.0 to 7.1.1. **This update includes a security fix.**
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](acornjs/acorn@7.1.0...7.1.1)

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