Bump gatsby-transformer-remark from 2.8.35 to 5.25.1

Bumps [gatsby-transformer-remark](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-transformer-remark) from 2.8.35 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:production
...

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

Author: dependabot[bot]

package.json

@@ -38,7 +38,7 @@
     "gatsby-remark-responsive-iframe": "^2.0.0",
     "gatsby-remark-smartypants": "^2.0.0",
     "gatsby-source-filesystem": "^2.0.0",
-    "gatsby-transformer-remark": "^2.0.0",
+    "gatsby-transformer-remark": "^5.25.1",
     "gatsby-transformer-sharp": "^2.3.18",
     "github-slugger": "^1.2.1",
     "glamor": "^2.20.40",