Bump gatsby and gatsby-plugin-canonical-urls

Bumps [gatsby](https://github.com/gatsbyjs/gatsby) and [gatsby-plugin-canonical-urls](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-canonical-urls). These dependencies needed to be updated together.

Updates `gatsby` from 2.32.9 to 3.0.3
- [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@2.32.9...gatsby@3.0.3)

Updates `gatsby-plugin-canonical-urls` from 2.10.0 to 3.0.0
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-canonical-urls/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/gatsby-plugin-canonical-urls@3.0.0/packages/gatsby-plugin-canonical-urls)

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