make crc 32 optional

mix.exs

@@ -4,7 +4,7 @@ defmodule ExSecrets.MixProject do
   def project do
     [
       app: :ex_secrets,
-      version: "0.3.3",
+      version: "0.3.4",
       elixir: "~> 1.13",
       build_embedded: Mix.env() == :prod,
       start_permanent: Mix.env() == :prod,
@@ -31,7 +31,6 @@ defmodule ExSecrets.MixProject do
       {:httpoison, "~> 1.8"},
       {:poison, "~> 3.1"},
       {:joken, "~> 2.6"},
-      {:crc32cer, "~> 0.1.10"},
 
       # Testing and Documentation
       {:mix_test_watch, "~> 1.0", only: [:dev, :test], runtime: false},
@@ -44,6 +43,17 @@ defmodule ExSecrets.MixProject do
       {:excoveralls, "~> 0.10", only: :test},
       {:credo, "~> 1.6", only: [:dev, :test], runtime: false}
     ]
+    |> require_crc_32()
+  end
+
+  defp require_crc_32(current_deps) do
+    case Application.get_env(:ex_secrets, :providers) do
+      %{"google_secret_manager" => _} ->
+        current_deps ++ [{:crc32cer, "~> 0.1.10"}]
+
+      _ ->
+        current_deps
+    end
   end
 
   defp description() do