FIX: enable building without token

setup.py

@@ -2,7 +2,6 @@ from setuptools import setup
 from distutils.command.build_py import build_py
 import subprocess
 import os
-import py_compile
 
 
 class APIGenBuild(build_py):
@@ -10,6 +9,8 @@ class APIGenBuild(build_py):
         build_versions = ['3.0', '3.1', '3.2']
         default_version = '3.2'
         environ = os.environ.copy()
+        if not environ.get('NETDB_TOKEN', False):
+            build_versions.remove('3.0')
         for version in build_versions:
             target_dir = os.path.join(self.build_lib, 'netdb_client', f"api{version.replace('.', '')}")
             self.mkpath(target_dir)