Bump gatsby-transformer-remark from 4.11.0 to 4.12.0

Bumps [gatsby-transformer-remark](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-transformer-remark) from 4.11.0 to 4.12.0.
- [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
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

package-lock.json

@@ -37,7 +37,7 @@
     "gatsby-plugin-sass": "4.0.0",
     "gatsby-plugin-sitemap": "^3.0.0",
     "gatsby-source-filesystem": "^3.0.0",
-    "gatsby-transformer-remark": "^4.11.0",
+    "gatsby-transformer-remark": "^4.12.0",
     "gatsby-transformer-yaml": "^3.0.0",
     "github-base": "^1.0.0",
     "history": "^4.7.2",