Remove CSS mapping too

Author: dhh

lib/tasks/clobber.rake

@@ -2,6 +2,7 @@ namespace :dartsass do
   desc "Remove CSS builds"
   task :clobber do
     rm_rf Dir["app/assets/builds/[^.]*.css"], verbose: false
+    rm_rf Dir["app/assets/builds/[^.]*.css\.map"], verbose: false
   end
 end