Update Hatchet
Update Hatchet

v4.0.12 introduced a fix for a deadlock in the reaper:
https://github.com/heroku/hatchet/pull/63/commits/446c280003a2fe8dfb0139905cfc7865fa5e69e3

# Conflicts:
#       Gemfile.lock

instacart/heroku-buildpack-ruby,heroku/heroku-buildpack-ruby,zunda/heroku-buildpack-ruby,makifund/heroku-buildpack-ruby,zunda/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,makifund/heroku-buildpack-ruby,Scalingo/ruby-buildpack,Genius/heroku-buildpack-ruby,brightbytes/heroku-buildpack-ruby-without-assets-precompile,pilotcreative/heroku-buildpack-ruby,orenyk/heroku-buildpack-ruby,heroku/heroku-buildpack-ruby,Scalingo/ruby-buildpack,orenyk/heroku-buildpack-ruby,Genius/heroku-buildpack-ruby,brightbytes/heroku-buildpack-ruby-without-assets-precompile,pilotcreative/heroku-buildpack-ruby