fix: pin sphinx<9 to fix docs build

sphinx-toolbox 4.1.2 imports sphinx.ext.autodoc.logger which was
removed in Sphinx 9.x. Pin until sphinx-toolbox releases a fix.

Closes #707

Author: andreahlert

pyproject.toml

@@ -103,7 +103,7 @@ tests = [
 
 documentation = [
   "apache-burr[tests]",
-  "sphinx",
+  "sphinx<9",
   "sphinx-autobuild",
   "myst-nb",
   "furo",