Add support for OTP 24 (#24)

:crypto.hmac/3 was removed in favor of :crypto.mac/4 which was introduced in OTP 22.1.

Co-authored-by: Tobias Schwab <tobstarr@gmail.com>
Co-authored-by: Aleksei Magusev <248290+lexmag@users.noreply.github.com>

lib/oauther.ex

@@ -60,8 +60,9 @@ defmodule OAuther do
   end
 
   def signature(verb, url, params, %Credentials{method: :hmac_sha1} = creds) do
-    :sha
-    |> :crypto.hmac(compose_key(creds), base_string(verb, url, params))
+    creds
+    |> compose_key()
+    |> hmac_sha(base_string(verb, url, params))
     |> Base.encode64()
   end
 
@@ -71,6 +72,17 @@ defmodule OAuther do
     |> Base.encode64()
   end
 
+  # TODO: Remove this once we require at minimum OTP 22.
+  if Code.ensure_loaded?(:crypto) and function_exported?(:crypto, :mac, 4) do
+    defp hmac_sha(key, data) do
+      :crypto.mac(:hmac, :sha, key, data)
+    end
+  else
+    defp hmac_sha(key, data) do
+      :crypto.hmac(:sha, key, data)
+    end
+  end
+
   defp protocol_param?({key, _value}) do
     String.starts_with?(key, "oauth_")
   end