Update conf.py to be compatible with Sphinx 4.1.2
Change-Id: I905911121fca48ae85f046bef714135cbf641d0a
diff --git a/docs/source/conf.py b/docs/source/conf.py
index c83468f..cc55b8a 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -246,7 +246,7 @@
# By default MathJax does not use TeX fonts, which is a tragedy. Also
# scaling the fonts down a bit makes them fit better with font sizing
# in the "Read The Docs" theme.
-mathjax_config = {
+mathjax3_config = {
'HTML-CSS' : {
'availableFonts' : ["TeX"],
'scale' : 90