fix(deps): bump gatsby-plugin-manifest from 5.11.0 to 5.12.0

Bumps [gatsby-plugin-manifest](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-manifest) from 5.11.0 to 5.12.0.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-manifest/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-manifest@5.12.0/packages/gatsby-plugin-manifest)

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

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

package.json

@@ -14,7 +14,7 @@
     "gatsby-plugin-catch-links": "^5.11.0",
     "gatsby-plugin-google-analytics": "^5.11.0",
     "gatsby-plugin-image": "^3.11.0",
-    "gatsby-plugin-manifest": "^5.11.0",
+    "gatsby-plugin-manifest": "^5.12.0",
     "gatsby-plugin-netlify": "^5.1.0",
     "gatsby-plugin-netlify-cms": "^7.11.0",
     "gatsby-plugin-offline": "^6.11.0",