build(deps): bump jupyter-book from 1.0.4.post1 to 2.1.2

Bumps [jupyter-book](https://github.com/jupyter-book/jupyter-book) from 1.0.4.post1 to 2.1.2.
- [Release notes](https://github.com/jupyter-book/jupyter-book/releases)
- [Commits](jupyter-book/jupyter-book@v1.0.4.post1...v2.1.2)

---
updated-dependencies:
- dependency-name: jupyter-book
  dependency-version: 2.1.2
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -54,7 +54,7 @@ lint = [
 
 docs = [
     "demesdraw",
-    "jupyter-book<2",
+    "jupyter-book<3",
     "piccolo_theme",
     "sphinx_issues",
     "sphinxcontrib-programoutput",