update the faraday connection/response handler to accept non-json responses (read: string)

Author: gregsaab

lib/slack/web/faraday/connection.rb

@@ -26,7 +26,7 @@ def connection
                 connection.request :url_encoded
                 connection.use ::Slack::Web::Faraday::Response::RaiseError
                 connection.response :mashify, mash_class: Slack::Messages::Message
-                connection.response :json, content_type: /\b*$/
+                connection.response :json, content_type: /\bjson$/
                 connection.use ::Slack::Web::Faraday::Response::WrapError
                 connection.response :logger, logger if logger
                 connection.adapter adapter

lib/slack/web/faraday/response/raise_error.rb

@@ -10,6 +10,7 @@ def on_complete(env)
             return unless env.success?
 
             body = env.body
+            return if env.success? && body.is_a?(String)
             return unless body
             return if body['ok']