chore: Update mix.exs

Author: gsmlg

mix.exs

@@ -1,22 +1,26 @@
 defmodule Phoenix.SessionProcess.MixProject do
   use Mix.Project
 
+  @version "0.3.1"
+  @source_url "https://github.com/gsmlg-dev/phoenix_session_process"
+
   def project do
     [
       app: :phoenix_session_process,
-      version: "0.3.1",
+      version: @version,
       elixir: "~> 1.14",
       elixirc_paths: elixirc_paths(Mix.env()),
       start_permanent: Mix.env() == :prod,
       description: description(),
-      source_url: "https://github.com/gsmlg-dev/phoenix_session_process",
+      source_url: @source_url,
       package: [
         files: ["lib", "mix.exs", "README*", "LICENSE*", "CHANGELOG*"],
         maintainers: ["Jonathan Gao"],
         licenses: ["MIT"],
-        links: %{"GitHub" => "https://github.com/gsmlg-dev/phoenix_session_process"}
+        links: %{"GitHub" => @source_url}
       ],
-      deps: deps()
+      deps: deps(),
+      docs: docs()
     ]
   end
 
@@ -31,7 +35,7 @@ defmodule Phoenix.SessionProcess.MixProject do
   defp deps do
     [
       {:plug, "~> 1.0"},
-      {:ex_doc, ">= 0.0.0", only: :dev, runtime: false}
+      {:ex_doc, ">= 0.0.0", only: :prod, runtime: false}
     ]
   end
 
@@ -43,4 +47,14 @@ defmodule Phoenix.SessionProcess.MixProject do
     Tool for create process for each user session in Phoenix.
     """
   end
+
+  defp docs do
+    [
+      extras: ["CHANGELOG.md", "README.md"],
+      source_url: @source_url,
+      source_ref: "v#{@version}",
+      main: "readme",
+      skip_undefined_reference_warnings_on: ["CHANGELOG.md"]
+    ]
+  end
 end