fix: upgrade @docusaurus/plugin-content-pages from 3.7.0 to 3.8.1

Snyk has created this PR to upgrade @docusaurus/plugin-content-pages from 3.7.0 to 3.8.1.

See this package in npm:
@docusaurus/plugin-content-pages

See this project in Snyk:
https://app.snyk.io/org/uber-open-source-reviews/project/ed3f3552-188c-4c71-ae58-d6ebbdc1e09d?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot