build(deps): bump gatsby-remark-images from 6.13.0 to 6.15.1 in /docs

Bumps [gatsby-remark-images](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-remark-images) from 6.13.0 to 6.15.1.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/[email protected]/packages/gatsby-remark-images/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/[email protected]/packages/gatsby-remark-images)

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

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

Author: dependabot[bot]

Diff for: docs/package-lock.json

@@ -29,7 +29,7 @@
     "gatsby-remark-autolink-headers": "^5.15.1",
     "gatsby-remark-copy-linked-files": "^5.13.0",
     "gatsby-remark-external-links": "^0.0.4",
-    "gatsby-remark-images": "^6.13.0",
+    "gatsby-remark-images": "^6.15.1",
     "gatsby-remark-mermaid": "^2.1.0",
     "gatsby-remark-responsive-iframe": "^5.13.0",
     "gatsby-source-filesystem": "^4.13.0",