Bump gatsby from 5.10.0 to 5.13.7 (#88)

Bumps [gatsby](https://github.com/gatsbyjs/gatsby) from 5.10.0 to 5.13.7.
- [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]@5.13.7)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>