Bump gatsby-plugin-feed from 5.12.3 to 5.13.1

Bumps [gatsby-plugin-feed](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-feed) from 5.12.3 to 5.13.1.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-feed/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/[email protected]/packages/gatsby-plugin-feed)

---
updated-dependencies:
- dependency-name: gatsby-plugin-feed
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

package.json

@@ -7,7 +7,7 @@
     "@mdx-js/react": "^3.0.0",
     "gatsby": "^5.12.9",
     "gatsby-core-utils": "^4.12.1",
-    "gatsby-plugin-feed": "^5.12.3",
+    "gatsby-plugin-feed": "^5.13.1",
     "gatsby-plugin-image": "^3.12.3",
     "gatsby-plugin-mdx": "^5.12.3",
     "gatsby-plugin-sharp": "^5.12.3",