Update gen_rpc to v2.3.1 (#2315)

Update gen_rpc to v2.3.1

Makefile

@@ -7,7 +7,7 @@ DEPS = jsx gproc gen_rpc ekka esockd cowboy replayq
 
 dep_jsx     = hex-emqx 2.9.0
 dep_gproc   = hex-emqx 0.8.0
-dep_gen_rpc = git-emqx https://github.com/emqx/gen_rpc 2.3.0
+dep_gen_rpc = git-emqx https://github.com/emqx/gen_rpc 2.3.1
 dep_esockd  = git-emqx https://github.com/emqx/esockd v5.4.4
 dep_ekka    = git-emqx https://github.com/emqx/ekka v0.5.3
 dep_cowboy  = hex-emqx 2.4.0

rebar.config

@@ -6,7 +6,7 @@
 
 %% appended to deps in rebar.config.script
 {github_emqx_deps,
-    [{gen_rpc, "2.3.0"},
+    [{gen_rpc, "2.3.1"},
      {ekka, "v0.5.3"},
      {replayq, "v0.1.1"},
      {esockd, "v5.4.4"},