add support for Excon connection options in hub requests

lib/discourse_hub.rb

@@ -39,23 +39,33 @@ module DiscourseHub
   end
 
   def self.singular_action(action, rel_url, params = {})
+    connect_opts = connect_opts(params)
     JSON.parse(Excon.send(action,
       "#{hub_base_url}#{rel_url}",
+      {
         headers: { 'Referer' => referer, 'Accept' => accepts.join(', ') },
         query: params,
         omit_default_port: true
+      }.merge(connect_opts)
     ).body)
   end
 
   def self.collection_action(action, rel_url, params = {})
+    connect_opts = connect_opts(params)
     JSON.parse(Excon.send(action,
       "#{hub_base_url}#{rel_url}",
+      {
         body: JSON[params],
         headers: { 'Referer' => referer, 'Accept' => accepts.join(', '), "Content-Type" => "application/json" },
         omit_default_port: true
+      }.merge(connect_opts)
     ).body)
   end
 
+  def self.connect_opts(params = {})
+    params.delete(:connect_opts)&.except(:body, :headers, :query) || {}
+  end
+
   def self.hub_base_url
     if Rails.env.production?
       ENV['HUB_BASE_URL'] || 'https://api.discourse.org/api'