use from initializer for faraday env since they provide it.

spec/support/responses.rb

@@ -1,7 +1,7 @@
 class Responses
   class << self
     def mock_faraday(code, headers, body)
-      env = Faraday::Env.new(status: code, response_headers: headers, response_body: body)
+      env = Faraday::Env.from(status: code, response_headers: headers, response_body: body)
       Faraday::Response.new(env)
     end
   end