Fix tox env

Author: mvdbeek

.github/workflows/pulsar.yaml

@@ -51,7 +51,7 @@ jobs:
           python: 3.11
         - tox-env: py311-test-unit
           python: 3.11
-        - tox-env: py37-install_wheel
+        - tox-env: py39-install_wheel
           python: 3.9
     services:
       job-files: