FIX: handle garbage in POST_VERSION

setup.py

@@ -15,6 +15,8 @@ for v in vers:
 latest_previous_util_version = os.environ.get('LATEST_UTIL_VERSION', None)
 latest_previous_api_version = os.environ.get('LATEST_API_VERSION', None)
 post_version = os.environ.get('POST_NUM', None)
+if not post_version.isdigit():
+    post_version = None
 
 def get_gen_version():
     ver = subprocess.run(["pip freeze | grep net_api_generator"], shell=True, text=True, check=True, capture_output=True).stdout