Merge pull request #419 from sblauth/dependabot/pip/sphinx-7.3.6

Bump sphinx from 7.2.6 to 7.3.6

docs/requirements.txt

@@ -1,7 +1,7 @@
 numpy>=1.22.2 # not directly required, pinned by Snyk to avoid a vulnerability
 matplotlib
 scipy
-Sphinx==7.2.6
+Sphinx==7.3.6
 sphinx-argparse==0.4.0
 sphinx-copybutton==0.5.2
 meshio==5.3.5