More stringent dependency version on extreme

[drozzy]

Instead of:

      {:extreme, "~> 0.11"},

we need to do:

      {:extreme, "~> 0.11.0"},

This is because with the first option, mix pulls down extreme 0.13 automatically, which depends on new elixir_uuid renamed library. Fixing to 0.11.0 makes it download extreme 0.11.

I fixed this in my fork. But you might want to fix it here if you don't want to accept the full PR for other stuff: #17