[appveyor] Use pytest via python module

mpsonntag · mpsonntag · commit 1a9780c4cf07 · 2021-06-21T16:52:32.000+02:00
diff --git a/appveyor.yml b/appveyor.yml
@@ -41,4 +41,4 @@ install:
 
 test_script:
   - python --version
-  - pytest
+  - python -m pytest
