chore(deps): bump gatsby-plugin-mdx from 5.12.0 to 5.12.1

Bumps [gatsby-plugin-mdx](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-mdx) from 5.12.0 to 5.12.1.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-mdx/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-mdx@5.12.1/packages/gatsby-plugin-mdx)

---
updated-dependencies:
- dependency-name: gatsby-plugin-mdx
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -60,7 +60,7 @@
     "gatsby": "^5.12.4",
     "gatsby-plugin-algolia": "^1.0.3",
     "gatsby-plugin-manifest": "^5.12.0",
-    "gatsby-plugin-mdx": "^5.12.0",
+    "gatsby-plugin-mdx": "^5.12.1",
     "gatsby-plugin-netlify": "^5.1.1",
     "gatsby-plugin-offline": "^6.12.1",
     "gatsby-plugin-plausible": "^0.0.7",