fix(deps): bump gatsby from 5.11.0 to 5.12.3

Bumps [gatsby](https://github.com/gatsbyjs/gatsby) from 5.11.0 to 5.12.3.
- [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@5.11.0...gatsby@5.12.3)

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

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