Fix argument delegation

Prior to this change, using childprocess in a Ruby 3 environment would
generate `wrong number of arguments` errors.

This commit attempts to address the errors by ensuring that we are
properly delegating arguments in childprocess and the abstract_process
classes.

lib/childprocess.rb

@@ -16,14 +16,14 @@ def new(*args)
       case os
       when :macosx, :linux, :solaris, :bsd, :cygwin, :aix
         if posix_spawn?
-          Unix::PosixSpawnProcess.new(args)
+          Unix::PosixSpawnProcess.new(*args)
         elsif jruby?
-          JRuby::Process.new(args)
+          JRuby::Process.new(*args)
         else
-          Unix::ForkExecProcess.new(args)
+          Unix::ForkExecProcess.new(*args)
         end
       when :windows
-        Windows::Process.new(args)
+        Windows::Process.new(*args)
       else
         raise Error, "unsupported platform #{platform_name.inspect}"
       end

lib/childprocess/abstract_process.rb

@@ -39,7 +39,7 @@ class AbstractProcess
     # @see ChildProcess.build
     #
 
-    def initialize(args)
+    def initialize(*args)
       unless args.all? { |e| e.kind_of?(String) }
         raise ArgumentError, "all arguments must be String: #{args.inspect}"
       end