Merge pull request #1400 from Libensemble/dependabot/pip/develop/matplotlib-3.9.2

Bump matplotlib from 3.9.1 to 3.9.2

Author: jmlarson1

install/testing_requirements.txt

@@ -6,4 +6,4 @@ pytest-timeout==2.3.1
 mock==5.1.0
 python-dateutil==2.9.0.post0
 anyio==4.4.0
-matplotlib==3.9.1
+matplotlib==3.9.2