Bump myst-parser from 2.0.0 to 4.0.0 in /docs (#303)

Bumps [myst-parser](https://github.com/executablebooks/MyST-Parser) from 2.0.0 to 4.0.0.
- [Release notes](https://github.com/executablebooks/MyST-Parser/releases)
- [Changelog](https://github.com/executablebooks/MyST-Parser/blob/master/CHANGELOG.md)
- [Commits](executablebooks/MyST-Parser@v2.0.0...v4.0.0)

---
updated-dependencies:
- dependency-name: myst-parser
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

docs/requirements.txt

@@ -1,4 +1,4 @@
 furo==2024.8.6
 sphinx==7.2.6
 sphinx-click==5.1.0
-myst_parser==2.0.0
+myst_parser==4.0.0