Filter unknown options before passing to Finch.request/3

Finch 0.21.0 validates the options keyword list and raises
ArgumentError when unknown keys are passed. Since v0.21.0, the only
allowed keys are :pool_timeout, :receive_timeout, :request_timeout,
and :pool_strategy.

Previously the entire options keyword list (including :finch_name) was
forwarded to Finch.request/3, which now fails with:

    ** (ArgumentError) unknown keys [:finch_name] in [finch_name: MyFinch],
       the allowed keys are: [:pool_timeout, :receive_timeout,
       :request_timeout, :pool_strategy]

Filter the options down to the keys Finch accepts before forwarding.

No new tests were added because this was already caught by the current
test suite after updating the finch dependency via
`test/aws/http_client_test.exs:82`

Fixes: #228
See: sneako/finch#365

Author: navinpeiris

lib/aws/http_client/finch.ex

@@ -20,15 +20,19 @@ defmodule AWS.HTTPClient.Finch do
 
   @behaviour AWS.HTTPClient
 
+  @finch_options [:pool_timeout, :receive_timeout, :request_timeout, :pool_strategy]
+
   @impl AWS.HTTPClient
   def request(method, url, body, headers, options) do
     ensure_finch_running!()
 
     finch_name = Keyword.get(options, :finch_name, AWS.Finch)
+    finch_options = Keyword.take(options, @finch_options)
+
     url = IO.iodata_to_binary(url)
     request = Finch.build(method, url, headers, body)
 
-    case Finch.request(request, finch_name, options) do
+    case Finch.request(request, finch_name, finch_options) do
       {:ok, response} ->
         {:ok, %{status_code: response.status, headers: response.headers, body: response.body}}