chore: pin rfc3339 0.2.3

dialyzer fix and mix file fix

mix.exs

@@ -97,6 +97,7 @@ defmodule EMQXUmbrella.MixProject do
       {:hackney, github: "emqx/hackney", tag: "1.18.1-1", override: true},
       # set by hackney (dependency)
       {:ssl_verify_fun, "1.1.7", override: true},
+      {:rfc3339, github: "emqx/rfc3339", tag: "0.2.3", override: true},
       {:uuid, github: "okeuday/uuid", tag: "v2.0.6", override: true},
       {:quickrand, github: "okeuday/quickrand", tag: "v2.0.6", override: true}
     ] ++

rebar.config

@@ -96,6 +96,7 @@
     , {jsone, {git, "https://github.com/emqx/jsone.git", {tag, "1.7.1"}}}
     , {uuid, {git, "https://github.com/okeuday/uuid.git", {tag, "v2.0.6"}}}
     , {ssl_verify_fun, "1.1.7"}
+    , {rfc3339, {git, "https://github.com/emqx/rfc3339.git", {tag, "0.2.3"}}}
     ]}.
 
 {xref_ignores,