Merge pull request #7321 from hugovk/azurepipelines-3.8-linux-macos

Azure Pipelines: Test Linux and macOS on Python 3.8

.azure-pipelines/jobs/test.yml

@@ -35,7 +35,10 @@ jobs:
       Python37:
         python.version: '3.7'
         python.architecture: x64
-    maxParallel: 3
+      Python38:
+        python.version: '3.8'
+        python.architecture: x64
+    maxParallel: 4
 
   steps:
   - template: ../steps/run-tests.yml