Move text URL check to the Haskell binary

lib/up2date.rb

@@ -77,7 +77,7 @@ module SlackBuilder
     end
 
     def latest
-      `./bin/slackbuilder #{@vendor} #{@name}`.strip
+      `./bin/slackbuilder packagist #{@vendor} #{@name}`.strip
     end
   end
 
@@ -86,14 +86,11 @@ module SlackBuilder
     def initialize(latest_url)
       super()
 
-      @latest_url = URI latest_url
+      @latest_url = latest_url
     end
 
     def latest
-      response = Net::HTTP.get @latest_url, {
-        'content-type' => 'text/plain'
-      }
-      response.strip
+      `./bin/slackbuilder text #{@latest_url}`.strip
     end
   end