chore(deps): unify version of hocon

apps/emqx/rebar.config

@@ -17,7 +17,7 @@
     , {esockd, {git, "https://github.com/emqx/esockd", {tag, "5.9.0"}}}
     , {ekka, {git, "https://github.com/emqx/ekka", {tag, "0.10.9"}}}
     , {gen_rpc, {git, "https://github.com/emqx/gen_rpc", {tag, "2.5.1"}}}
-    , {hocon, {git, "https://github.com/emqx/hocon.git", {tag, "0.19.6"}}}
+    , {hocon, {git, "https://github.com/emqx/hocon.git", {tag, "0.20.3"}}}
     , {pbkdf2, {git, "https://github.com/emqx/erlang-pbkdf2.git", {tag, "2.0.4"}}}
     , {recon, {git, "https://github.com/ferd/recon", {tag, "2.5.1"}}}
     , {snabbkaffe, {git, "https://github.com/kafka4beam/snabbkaffe.git", {tag, "0.14.1"}}}