Update pinned oldest win image on azure

The windows-2019 image will be deprecated on 1.6.2025.
Also, this is a test whether the timeouts matplotlib#29797 are related to the
windows-2019 image.

Author: timhoffm

azure-pipelines.yml

@@ -50,7 +50,7 @@ stages:
         strategy:
           matrix:
             Windows_py311:
-              vmImage: 'windows-2019'  # keep one job pinned to the oldest image
+              vmImage: 'windows-2022'  # Keep one job pinned to the oldest image
               python.version: '3.11'
             Windows_py312:
               vmImage: 'windows-latest'