Fix ConnecitonPool deadlocking after reaching the connection limit

The issue was with ConcurrentLimiter not decrementing counters on
overload. It was fixed in the latest commit, but concurrentlimiter
version wasn't updated in Pleroma for some reason.

Closes #1977

mix.exs

@@ -178,7 +178,7 @@ defmodule Pleroma.Mixfile do
       {:flake_id, "~> 0.1.0"},
       {:concurrent_limiter,
        git: "https://git.pleroma.social/pleroma/elixir-libraries/concurrent_limiter.git",
-       ref: "8eee96c6ba39b9286ec44c51c52d9f2758951365"},
+       ref: "55e92f84b4ed531bd487952a71040a9c69dc2807"},
       {:remote_ip,
        git: "https://git.pleroma.social/pleroma/remote_ip.git",
        ref: "b647d0deecaa3acb140854fe4bda5b7e1dc6d1c8"},

mix.lock

@@ -14,7 +14,7 @@
   "certifi": {:hex, :certifi, "2.5.2", "b7cfeae9d2ed395695dd8201c57a2d019c0c43ecaf8b8bcb9320b40d6662f340", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm", "3b3b5f36493004ac3455966991eaf6e768ce9884693d9968055aeeeb1e575040"},
   "combine": {:hex, :combine, "0.10.0", "eff8224eeb56498a2af13011d142c5e7997a80c8f5b97c499f84c841032e429f", [:mix], [], "hexpm", "1b1dbc1790073076580d0d1d64e42eae2366583e7aecd455d1215b0d16f2451b"},
   "comeonin": {:hex, :comeonin, "5.3.1", "7fe612b739c78c9c1a75186ef2d322ce4d25032d119823269d0aa1e2f1e20025", [:mix], [], "hexpm", "d6222483060c17f0977fad1b7401ef0c5863c985a64352755f366aee3799c245"},
-  "concurrent_limiter": {:git, "https://git.pleroma.social/pleroma/elixir-libraries/concurrent_limiter.git", "8eee96c6ba39b9286ec44c51c52d9f2758951365", [ref: "8eee96c6ba39b9286ec44c51c52d9f2758951365"]},
+  "concurrent_limiter": {:git, "https://git.pleroma.social/pleroma/elixir-libraries/concurrent_limiter.git", "55e92f84b4ed531bd487952a71040a9c69dc2807", [ref: "55e92f84b4ed531bd487952a71040a9c69dc2807"]},
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm", "4a0850c9be22a43af9920a71ab17c051f5f7d45c209e40269a1938832510e4d9"},
   "cors_plug": {:hex, :cors_plug, "2.0.2", "2b46083af45e4bc79632bd951550509395935d3e7973275b2b743bd63cc942ce", [:mix], [{:plug, "~> 1.8", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "f0d0e13f71c51fd4ef8b2c7e051388e4dfb267522a83a22392c856de7e46465f"},
   "cowboy": {:hex, :cowboy, "2.8.0", "f3dc62e35797ecd9ac1b50db74611193c29815401e53bac9a5c0577bd7bc667d", [:rebar3], [{:cowlib, "~> 2.9.1", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm", "4643e4fba74ac96d4d152c75803de6fad0b3fa5df354c71afdd6cbeeb15fac8a"},