update unit tests versions

Author: ohmayr

owlbot.py

@@ -215,7 +215,11 @@ def docfx(session):
 s.replace(
     "noxfile.py",
     """nox.options.sessions = \[
-    "unit",
+    "unit-3.9",
+    "unit-3.10",
+    "unit-3.11",
+    "unit-3.12",
+    "unit-3.13",
     "system",""",
     """nox.options.sessions = [
     "unit",