chore: mix clean removes rustler artifacts.

mix.exs

@@ -16,6 +16,7 @@ defmodule Scenic.Driver.Renderling.MixProject do
       description: @description,
       deps: deps(),
       elixirc_paths: elixirc_paths(Mix.env()),
+      aliases: aliases(),
       docs: [
         main: "readme",
         extras: ["README.md"]
@@ -63,4 +64,15 @@ defmodule Scenic.Driver.Renderling.MixProject do
 
   defp elixirc_paths(env) when env in [:dev, :test], do: ["lib", "test/support"]
   defp elixirc_paths(_), do: ["lib"]
+
+  def aliases do
+    [clean: ["clean", &clean_rustler_artifacts/1]]
+  end
+
+  def clean_rustler_artifacts(_) do
+    __DIR__
+    |> Path.join("priv/native/*")
+    |> Path.wildcard()
+    |> Enum.each(&File.rm!/1)
+  end
 end