build: Bump acorn from 5.7.1 to 5.7.4#21

dependabot[bot] wants to merge 1 commit intomainarjankowski/boxcli:mainfrom

dependabot/npm_and_yarn/acorn-5.7.4arjankowski/boxcli:dependabot/npm_and_yarn/acorn-5.7.4Copy head branch name to clipboard