Bump markdown-it and @wordpress/scripts (#454)

Bumps [markdown-it](https://github.com/markdown-it/markdown-it) and [@wordpress/scripts](https://github.com/WordPress/gutenberg/tree/HEAD/packages/scripts). These dependencies needed to be updated together.

Updates `markdown-it` from 12.0.4 to 12.3.2
- [Release notes](https://github.com/markdown-it/markdown-it/releases)
- [Changelog](https://github.com/markdown-it/markdown-it/blob/master/CHANGELOG.md)
- [Commits](markdown-it/markdown-it@12.0.4...12.3.2)

Updates `@wordpress/scripts` from 22.3.0 to 22.5.0
- [Release notes](https://github.com/WordPress/gutenberg/releases)
- [Changelog](https://github.com/WordPress/gutenberg/blob/trunk/packages/scripts/CHANGELOG.md)
- [Commits](https://github.com/WordPress/gutenberg/commits/@wordpress/[email protected]/packages/scripts)

---
updated-dependencies:
- dependency-name: markdown-it
  dependency-type: indirect
- dependency-name: "@wordpress/scripts"
  dependency-type: direct:development
...

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

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