Bump gatsby-transformer-remark from 2.16.1 to 5.25.1

Bumps [gatsby-transformer-remark](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-transformer-remark) from 2.16.1 to 5.25.1.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-transformer-remark/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/[email protected]/packages/gatsby-transformer-remark)

---
updated-dependencies:
- dependency-name: gatsby-transformer-remark
  dependency-type: direct:development
...

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