.buildpacks in potassium-5.2.2

- old
+ new

@@ -1,3 +1,2 @@
 https://github.com/platanus/heroku-buildpack-ruby-version.git
 https://github.com/heroku/heroku-buildpack-ruby.git
-https://github.com/gunpowderlabs/buildpack-ruby-rake-deploy-tasks.git