update deps to solve some bugs

[wolverineks]

some bugs experienced that will be fixed in upcoming versions of various dependencies
gettext - changing error tags
ecto - changing concurrent testing

some deps set to github repo
may be solved with a simple mix deps.get

[wolverineks]

use

def translate_error({msg, opts}) do
  Gettext.dngettext(Raffler.Gettext, "errors", msg, msg, opts[:count] || 1, opts)
end

in web/views/error_helpers.ex as workaround for error_tag bug