build(deps): bump gatsby from 2.29.3 to 2.32.3 in /docs

Bumps [gatsby](https://github.com/gatsbyjs/gatsby) from 2.29.3 to 2.32.3.
- [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/[email protected]@2.32.3)

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

Author: dependabot[bot]