Bump gatsby from 3.0.4 to 3.1.0

Bumps [gatsby](https://github.com/gatsbyjs/gatsby) from 3.0.4 to 3.1.0.
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/compare/gatsby@3.0.4...gatsby@3.1.0)

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

package.json

@@ -37,7 +37,7 @@
     "date-fns": "^2.19.0",
     "date-fns-tz": "^1.1.3",
     "eslint-plugin-mdx": "^1.9.1",
-    "gatsby": "^3.0.4",
+    "gatsby": "^3.1.0",
     "gatsby-link": "^3.0.1",
     "gatsby-plugin-alias-imports": "^1.0.5",
     "gatsby-plugin-google-gtag": "^3.0.0",