tests: include pypy3.9 in nox if present

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

noxfile.py

@@ -5,7 +5,17 @@
 nox.needs_version = ">=2022.1.7"
 nox.options.sessions = ["lint", "tests", "tests_packaging"]
 
-PYTHON_VERSIONS = ["3.6", "3.7", "3.8", "3.9", "3.10", "3.11", "pypy3.7", "pypy3.8"]
+PYTHON_VERSIONS = [
+    "3.6",
+    "3.7",
+    "3.8",
+    "3.9",
+    "3.10",
+    "3.11",
+    "pypy3.7",
+    "pypy3.8",
+    "pypy3.9",
+]
 
 if os.environ.get("CI", None):
     nox.options.error_on_missing_interpreters = True