Introduce forgotten resign parameter...

... for the POST /source/{project_name}?cmd=copy API endpoint

This parameter should have been included in this commit:
a19f13e

src/api/app/controllers/source_controller.rb

@@ -702,7 +702,7 @@ def project_command_copy
     end
 
     job_params = params.slice(
-      :cmd, :user, :comment, :oproject, :withbinaries, :withhistory, :makeolder, :makeoriginolder, :noservice
+      :cmd, :user, :comment, :oproject, :withbinaries, :withhistory, :makeolder, :makeoriginolder, :noservice, :resign
     ).permit!.to_h
     job_params[:user] = User.session!.login