Pin jupyter-book <2

Author: benjeffery

pyproject.toml

@@ -74,7 +74,7 @@ test = [
     "scipy==1.15.3",
 ]
 docs = [
-    "jupyter-book==1.0.4.post1",
+    "jupyter-book==1.0.4.post1,<2",
     "matplotlib==3.10.6",
     "msprime==1.3.4",
     "numba==0.61.2",
@@ -84,7 +84,7 @@ docs = [
     "tskit==0.6.4",
 ]
 dev = [
-    "jupyter-book",
+    "jupyter-book<2",
     "matplotlib",
     "msprime",
     "numba",