[Security] Bump acorn from 6.3.0 to 6.4.1 in /website (#7765)
Bumps [acorn](https://github.com/acornjs/acorn) from 6.3.0 to 6.4.1. **This update includes a security fix.**
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/6.3.0...6.4.1)
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Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>