ipset: Fix dumb bug due to future not awaited

The edge case is so dumb, cargo is supposed to tell me about this ><

Just learnt that Python never warns about this btw:
https://trio.readthedocs.io/en/v0.9.0/tutorial.html#warning-don-t-forget-that-await

plugins/reaction-plugin-ipset/src/main.rs

@@ -124,7 +124,7 @@ impl PluginInfo for Plugin {
 
         // Launch all actions
         while let Some(action) = self.actions.pop() {
-            tokio::spawn(async move { action.serve() });
+            tokio::spawn(async move { action.serve().await });
         }
         self.actions = Default::default();