chore: fix mix compiling failures

apps/emqx_gateway_ocpp/rebar.config

@@ -1,3 +1,6 @@
 {deps, [
-    {jesse, "1.7.0"}
+    {jesse, "1.7.0"},
+    {emqx, {path, "../../apps/emqx"}},
+    {emqx_utils, {path, "../emqx_utils"}},
+    {emqx_gateway, {path, "../../apps/emqx_gateway"}}
 ]}.