Bump gatsby from 3.14.2 to 4.25.7

Bumps [gatsby](https://github.com/gatsbyjs/gatsby) from 3.14.2 to 4.25.7.
- [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/[email protected]@4.25.7)

---
updated-dependencies:
- dependency-name: gatsby
  dependency-type: direct:production
...

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

package.json

@@ -28,7 +28,7 @@
     "bootstrap-italia": "^1.4.3",
     "classnames": "^2.3.1",
     "design-react-kit": "^3.3.3",
-    "gatsby": "^3.14.2",
+    "gatsby": "^4.25.7",
     "gatsby-plugin-google-tagmanager": "3.14.0",
     "gatsby-plugin-image": "^1.14.1",
     "gatsby-plugin-matomo": "0.10.0",