Bump gatsby-remark-smartypants from 4.11.0 to 6.12.0

Bumps [gatsby-remark-smartypants](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-remark-smartypants) from 4.11.0 to 6.12.0.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-remark-smartypants/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-remark-smartypants@6.12.0/packages/gatsby-remark-smartypants)

---
updated-dependencies:
- dependency-name: gatsby-remark-smartypants
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -28,7 +28,7 @@
     "gatsby-remark-images": "^5.11.0",
     "gatsby-remark-prismjs": "^5.11.0",
     "gatsby-remark-responsive-iframe": "^4.11.0",
-    "gatsby-remark-smartypants": "^4.11.0",
+    "gatsby-remark-smartypants": "^6.12.0",
     "gatsby-source-filesystem": "^3.14.0",
     "gatsby-transformer-remark": "^4.11.0",
     "gatsby-transformer-sharp": "^3.14.0",