Bump @mdx-js/loader from 3.0.1 to 3.1.0 in /src

Bumps [@mdx-js/loader](https://github.com/mdx-js/mdx/tree/HEAD/packages/loader) from 3.0.1 to 3.1.0.
- [Release notes](https://github.com/mdx-js/mdx/releases)
- [Changelog](https://github.com/mdx-js/mdx/blob/main/changelog.md)
- [Commits](https://github.com/mdx-js/mdx/commits/3.1.0/packages/loader)

---
updated-dependencies:
- dependency-name: "@mdx-js/loader"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>