Update python classifier for python 3.10

In 2023.1 cycle, we are testing the python 3.10
as voting job so updating the python classifier.

Currently we have python 3.8 unit test job running on
Ubuntu Focal and python 3.10 job on Ubuntu Jammy.

Change-Id: Ie5ef1e398f6709e2164db57c3f5bbfbc69053a02

setup.cfg

@@ -22,6 +22,7 @@ classifier =
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
 
 [files]
 packages =