Bump scss-tokenizer, gatsby-plugin-sass and node-sass

Bumps [scss-tokenizer](https://github.com/sasstools/scss-tokenizer) to 0.4.3 and updates ancestor dependencies [scss-tokenizer](https://github.com/sasstools/scss-tokenizer), [gatsby-plugin-sass](https://github.com/gatsbyjs/gatsby/tree/HEAD/packages/gatsby-plugin-sass) and [node-sass](https://github.com/sass/node-sass). These dependencies need to be updated together.


Updates `scss-tokenizer` from 0.2.3 to 0.4.3
- [Release notes](https://github.com/sasstools/scss-tokenizer/releases)
- [Commits](sasstools/scss-tokenizer@v0.2.3...v0.4.3)

Updates `gatsby-plugin-sass` from 2.3.22 to 5.24.0
- [Release notes](https://github.com/gatsbyjs/gatsby/releases)
- [Changelog](https://github.com/gatsbyjs/gatsby/blob/master/packages/gatsby-plugin-sass/CHANGELOG.md)
- [Commits](https://github.com/gatsbyjs/gatsby/commits/[email protected]/packages/gatsby-plugin-sass)

Updates `node-sass` from 4.14.1 to 7.0.3
- [Release notes](https://github.com/sass/node-sass/releases)
- [Changelog](https://github.com/sass/node-sass/blob/master/CHANGELOG.md)
- [Commits](sass/node-sass@v4.14.1...v7.0.3)

---
updated-dependencies:
- dependency-name: scss-tokenizer
  dependency-type: indirect
- dependency-name: gatsby-plugin-sass
  dependency-type: direct:production
- dependency-name: node-sass
  dependency-type: direct:production
...

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