Bump acorn (#3003)
Bumps [acorn](https://github.com/acornjs/acorn) from 5.7.3 to 5.7.4.
- [Release notes](https://github.com/acornjs/acorn/releases)
- [Commits](https://github.com/acornjs/acorn/compare/5.7.3...5.7.4)
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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Reviewed-by: Gergely Pollak <shuzirra@cloudera.com>