add OUTPOST_FLAVORS_UPDATE_TOKEN as env variable when starting servers

jsc_custom/spawner/spawner.py

@@ -353,6 +353,10 @@ async def custom_env(spawner, user_options, jupyterhub_api_url):
         env[
             "JUPYTERHUB_FLAVORS_UPDATE_URL"
         ] = f"{jupyterhub_api_url.rstrip('/')}/outpostflavors/{system}"
+        if os.environ.get("OUTPOST_FLAVORS_UPDATE_TOKEN", None):
+            env["JUPYTERHUB_FLAVORS_UPDATE_TOKEN"] = os.environ.get(
+                "OUTPOST_FLAVORS_UPDATE_TOKEN", ""
+            )
     return env