chore(backend): update dependency guardian to v2

Author: plural-renovate[bot]

apps/api/mix.exs

@@ -72,7 +72,7 @@ defmodule Api.MixProject do
       {:phoenix_live_reload, "~> 1.2", only: :dev},
       {:gettext, "~> 0.20"},
       {:jason, "~> 1.0"},
-      {:guardian, "~> 1.2.1"},
+      {:guardian, "~> 2.3.0"},
       {:cors_plug, "~> 2.0"},
       {:plug_cowboy, "~> 2.6.0", override: true},
       {:reverse_proxy_plug, "~> 2.1.1"},

apps/core/mix.exs

@@ -78,7 +78,7 @@ defmodule Core.MixProject do
       {:bourne, "~> 1.1"},
       {:flow, "~> 0.15.0"},
       {:joken, "~> 2.5.0"},
-      {:guardian, "~> 1.2.1"},
+      {:guardian, "~> 2.3.0"},
       {:arc, "~> 0.11.0"},
       {:arc_gcs, "~> 0.2.0"},
       {:porcelain, "~> 2.0"},