Bump myst-nb from 1.1.2 to 1.2.0 in /docs (#520)

Bumps [myst-nb](https://github.com/executablebooks/myst-nb) from 1.1.2 to 1.2.0.
- [Release notes](https://github.com/executablebooks/myst-nb/releases)
- [Changelog](https://github.com/executablebooks/MyST-NB/blob/master/CHANGELOG.md)
- [Commits](executablebooks/MyST-NB@v1.1.2...v1.2.0)

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

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

Author: dependabot[bot]

docs/requirements.txt

@@ -2,5 +2,5 @@ furo==2024.8.6
 sphinx==8.1.3
 sphinx-click==6.0.0
 sphinx-copybutton==0.5.2
-myst-nb==1.1.2
+myst-nb==1.2.0
 linkify-it-py==2.0.3