Bump myst-parser from 0.17.2 to 0.18.0

Bumps [myst-parser](https://github.com/executablebooks/MyST-Parser) from 0.17.2 to 0.18.0.
- [Release notes](https://github.com/executablebooks/MyST-Parser/releases)
- [Changelog](https://github.com/executablebooks/MyST-Parser/blob/master/CHANGELOG.md)
- [Commits](executablebooks/MyST-Parser@v0.17.2...v0.18.0)

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

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

docs/requirements.txt

@@ -1,5 +1,5 @@
 Sphinx==4.5.0
 importlib-metadata==4.11.3
-myst-parser==0.17.2
+myst-parser==0.18.0
 readthedocs-sphinx-search==0.1.2
 sphinx-book-theme==0.3.2