Use a 24 character state parameter

fhirclient/auth.py

@@ -200,7 +200,7 @@ def _authorize_params(self, server):
         if server is None:
             raise Exception("Cannot create an authorize-uri without server instance")
         if self.auth_state is None:
-            self.auth_state = str(uuid.uuid4())[:8]
+            self.auth_state = uuid.uuid4().hex[:24]
             server.should_save_state()
 
         params = {