fix(gen_rpc): the port discovery not working on a large offset

rebar.config

@@ -43,7 +43,7 @@
     , {cowboy, {git, "https://github.com/emqx/cowboy", {tag, "2.8.2"}}}
     , {esockd, {git, "https://github.com/emqx/esockd", {tag, "5.8.0"}}}
     , {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.8.1"}}}
-    , {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.5.0"}}}
+    , {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.5.1"}}}
     , {cuttlefish, {git, "https://github.com/emqx/cuttlefish", {tag, "v3.3.3"}}}
     , {minirest, {git, "https://github.com/emqx/minirest", {tag, "0.3.5"}}}
     , {ecpool, {git, "https://github.com/emqx/ecpool", {tag, "0.5.0"}}}