Bump gatsby-remark-smartypants from 6.12.0 to 6.13.1 (#979)

Bumps [gatsby-remark-smartypants](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-remark-smartypants) from 6.12.0 to 6.13.1.
- [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@6.13.1/packages/gatsby-remark-smartypants)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

package.json

@@ -40,7 +40,7 @@
  "gatsby-remark-copy-linked-files": "^6.13.1",
  "gatsby-remark-images": "^7.12.0",
  "gatsby-remark-prismjs": "^7.13.1",
- "gatsby-remark-smartypants": "^6.12.0",
+ "gatsby-remark-smartypants": "^6.13.1",
  "gatsby-source-filesystem": "^5.12.0",
  "gatsby-transformer-asciidoc": "^4.12.0",
  "gatsby-transformer-remark": "^6.12.0",