Switch to a fork of Hackney 1.15.2 for now so we can have our URL normalization bugfix

mix.exs

@@ -206,7 +206,10 @@ defmodule Pleroma.Mixfile do
       {:mock, "~> 0.3.5", only: :test},
       # temporary downgrade for excoveralls, hackney until hackney max_connections bug will be fixed
       {:excoveralls, "0.12.3", only: :test},
-      {:hackney, "1.15.2", override: true},
+      {:hackney,
+       git: "https://git.pleroma.social/pleroma/elixir-libraries/hackney.git",
+       ref: "7d7119f0651515d6d7669c78393fd90950a3ec6e",
+       override: true},
       {:mox, "~> 0.5", only: :test},
       {:websocket_client, git: "https://github.com/jeremyong/websocket_client.git", only: :test}
     ] ++ oauth_deps()