fix(topic metrics): add appup.src

src/emqx.appup.src

@@ -8,7 +8,8 @@
 {"4.2.2",
   [
     {"4.2.1", [
-      {load_module, emqx_channel, brutal_purge, soft_purge, []}
+      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+      {load_module, emqx_mod_topic_metrics, brutal_purge, soft_purge, []}
     ]},
     {"4.2.0", [
       {load_module, emqx_channel, brutal_purge, soft_purge, []},
@@ -20,7 +21,8 @@
   ],
   [
     {"4.2.1", [
-      {load_module, emqx_channel, brutal_purge, soft_purge, []}
+      {load_module, emqx_channel, brutal_purge, soft_purge, []},
+      {load_module, emqx_mod_topic_metrics, brutal_purge, soft_purge, []}
     ]},
     {"4.2.0", [
       {load_module, emqx_channel, brutal_purge, soft_purge, []}