deprecating the .plugins, as it's not compatible with sending plugin options

lib/httpx/chainable.rb

@@ -28,13 +28,20 @@ module HTTPX
       branch(default_options).wrap(&blk)
     end
 
-    def plugin(*plugins)
+    def plugin(*args, **opts)
       klass = is_a?(Session) ? self.class : Session
       klass = Class.new(klass)
       klass.instance_variable_set(:@default_options, klass.default_options.merge(default_options))
-      klass.plugins(plugins).new
+      klass.plugin(*args, **opts).new
+    end
+
+    # deprecated
+    def plugins(*args, **opts)
+      klass = is_a?(Session) ? self.class : Session
+      klass = Class.new(klass)
+      klass.instance_variable_set(:@default_options, klass.default_options.merge(default_options))
+      klass.plugins(*args, **opts).new
     end
-    alias_method :plugins, :plugin
 
     def with(options, &blk)
       branch(default_options.merge(options), &blk)

lib/httpx/session.rb

@@ -251,12 +251,15 @@ module HTTPX
         self
       end
 
+      # :nocov:
       def plugins(pls)
+        warn ":#{__method__} is deprecated, use :plugin instead"
         pls.each do |pl, *args|
           plugin(pl, *args)
         end
         self
       end
+      # :nocov:
     end
 
     plugin(:proxy) unless ENV.grep(/https?_proxy$/i).empty?

test/support/requests/plugins/cookies.rb

@@ -43,7 +43,7 @@ module Requests
       end
 
       def test_plugin_cookies_follow
-        session = HTTPX.plugins(:follow_redirects, :cookies)
+        session = HTTPX.plugin(:follow_redirects).plugin(:cookies)
         session_cookies = { "a" => "b", "c" => "d" }
         session_uri = cookies_set_uri(session_cookies)