fix: upgrade @code-hike/mdx from 0.7.4 to 0.9.0

Snyk has created this PR to upgrade @code-hike/mdx from 0.7.4 to 0.9.0.

See this package in npm:
@code-hike/mdx

See this project in Snyk:
https://app.snyk.io/org/sammyfilly/project/9fce9ba0-c60e-42d7-9f98-290620d8b747?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot