Bump mpl-sphinx-theme version

Author: dstansby

requirements/doc/doc-requirements.txt

@@ -14,8 +14,7 @@ ipywidgets
 ipykernel
 numpydoc>=1.0
 packaging>=20
-pydata-sphinx-theme~=0.15.0
-mpl-sphinx-theme~=3.9.0
+mpl-sphinx-theme~=3.10.0
 pyyaml
 PyStemmer
 sphinxcontrib-svg2pdfconverter>=1.1.0