chore(appup): supply the appup instructions

apps/emqx_lwm2m/src/emqx_lwm2m.appup.src

@@ -0,0 +1,15 @@
+%% -*-: erlang -*-
+{VSN,
+  [
+    {"4.3.0", [
+      {load_module, emqx_lwm2m_protocol, brutal_purge, soft_purge, []}
+    ]},
+    {<<".*">>, []}
+  ],
+  [
+    {"4.3.0", [
+      {load_module, emqx_lwm2m_protocol, brutal_purge, soft_purge, []}
+    ]},
+   {<<".*">>, []}
+  ]
+}.