[Snyk] Upgrade @metalsmith/markdown from 1.6.0 to 1.8.0#205

NOUIY wants to merge 1 commit intomainNOUIY/nodejs.org:mainfrom

snyk-upgrade-9b285cd0b1be2586c35d8c50195b475fNOUIY/nodejs.org:snyk-upgrade-9b285cd0b1be2586c35d8c50195b475fCopy head branch name to clipboard