Bump guardian from 1.2.1 to 2.0.0

Bumps [guardian](https://github.com/ueberauth/guardian) from 1.2.1 to 2.0.0.
- [Release notes](https://github.com/ueberauth/guardian/releases)
- [Changelog](https://github.com/ueberauth/guardian/blob/master/CHANGELOG.md)
- [Commits](ueberauth/guardian@v1.2.1...v2.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Author: dependabot-preview[bot]

mix.exs

@@ -48,7 +48,7 @@ defmodule OpensourceChallenge.Mixfile do
       {:ja_serializer, "~> 0.15.0"},
       {:ja_resource, "~> 0.3.0"},
       {:bcrypt_elixir, "~> 2.0"},
-      {:guardian, "~> 1.2.1"},
+      {:guardian, "~> 2.0.0"},
       {:canada, "~> 2.0.0", override: true},
       {:canary, "~> 1.1.0"},
       {:gettext, "~> 0.11"},

mix.lock

@@ -8,16 +8,16 @@
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm"},
   "cors_plug": {:hex, :cors_plug, "2.0.0", "238ddb479f92b38f6dc1ae44b8d81f0387f9519101a6da442d543ab70ee0e482", [:mix], [{:plug, "~> 1.3 or ~> 1.4 or ~> 1.5", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
   "coverex": {:hex, :coverex, "1.5.0", "a4248302f09562993041f1b056866bfd5688d3a03c429de80c47ea6663989ecc", [:mix], [{:hackney, "~> 1.5", [hex: :hackney, repo: "hexpm", optional: false]}, {:poison, "~> 3.0 or ~> 3.1 or ~> 4.0", [hex: :poison, repo: "hexpm", optional: false]}], "hexpm"},
-  "cowboy": {:hex, :cowboy, "2.6.3", "99aa50e94e685557cad82e704457336a453d4abcb77839ad22dbe71f311fcc06", [:rebar3], [{:cowlib, "~> 2.7.3", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
-  "cowlib": {:hex, :cowlib, "2.7.3", "a7ffcd0917e6d50b4d5fb28e9e2085a0ceb3c97dea310505f7460ff5ed764ce9", [:rebar3], [], "hexpm"},
+  "cowboy": {:hex, :cowboy, "2.7.0", "91ed100138a764355f43316b1d23d7ff6bdb0de4ea618cb5d8677c93a7a2f115", [], [{:cowlib, "~> 2.8.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
+  "cowlib": {:hex, :cowlib, "2.8.0", "fd0ff1787db84ac415b8211573e9a30a3ebe71b5cbff7f720089972b2319c8a4", [], [], "hexpm"},
   "db_connection": {:hex, :db_connection, "1.1.3", "89b30ca1ef0a3b469b1c779579590688561d586694a3ce8792985d4d7e575a61", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},
   "decimal": {:hex, :decimal, "1.8.0", "ca462e0d885f09a1c5a342dbd7c1dcf27ea63548c65a65e67334f4b61803822e", [], [], "hexpm"},
   "dogma": {:hex, :dogma, "0.1.16", "3c1532e2f63ece4813fe900a16704b8e33264da35fdb0d8a1d05090a3022eef9", [:mix], [{:poison, ">= 2.0.0", [hex: :poison, repo: "hexpm", optional: false]}], "hexpm"},
   "ecto": {:hex, :ecto, "2.2.12", "ce7f619c1451daad0f59e8f01fd8e2584226171dc273e3346444446a13d93943", [:mix], [{:db_connection, "~> 1.1", [hex: :db_connection, repo: "hexpm", optional: true]}, {:decimal, "~> 1.2", [hex: :decimal, repo: "hexpm", optional: false]}, {:mariaex, "~> 0.8.0", [hex: :mariaex, repo: "hexpm", optional: true]}, {:poison, "~> 2.2 or ~> 3.0", [hex: :poison, repo: "hexpm", optional: true]}, {:poolboy, "~> 1.5", [hex: :poolboy, repo: "hexpm", optional: false]}, {:postgrex, "~> 0.13.0", [hex: :postgrex, repo: "hexpm", optional: true]}, {:sbroker, "~> 1.0", [hex: :sbroker, repo: "hexpm", optional: true]}], "hexpm"},
   "elixir_make": {:hex, :elixir_make, "0.5.2", "96a28c79f5b8d34879cd95ebc04d2a0d678cfbbd3e74c43cb63a76adf0ee8054", [:mix], [], "hexpm"},
   "elixir_uuid": {:hex, :elixir_uuid, "1.2.0", "ff26e938f95830b1db152cb6e594d711c10c02c6391236900ddd070a6b01271d", [:mix], [], "hexpm"},
   "gettext": {:hex, :gettext, "0.17.1", "8baab33482df4907b3eae22f719da492cee3981a26e649b9c2be1c0192616962", [:mix], [], "hexpm"},
-  "guardian": {:hex, :guardian, "1.2.1", "bdc8dd3dbf0fb7216cb6f91c11831faa1a64d39cdaed9a611e37f2413e584983", [:mix], [{:jose, "~> 1.8", [hex: :jose, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.3", [hex: :phoenix, repo: "hexpm", optional: true]}, {:plug, "~> 1.3.3 or ~> 1.4", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm"},
+  "guardian": {:hex, :guardian, "2.0.0", "5d3e537832b7cf35c8674da92457b7be671666a2eff4bf0f2ccfcfb3a8c67a0b", [:mix], [{:jose, "~> 1.8", [hex: :jose, repo: "hexpm", optional: false]}, {:plug, "~> 1.3.3 or ~> 1.4", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm"},
   "hackney": {:hex, :hackney, "1.15.1", "9f8f471c844b8ce395f7b6d8398139e26ddca9ebc171a8b91342ee15a19963f4", [:rebar3], [{:certifi, "2.5.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
   "httpoison": {:hex, :httpoison, "0.10.0", "4727b3a5e57e9a4ff168a3c2883e20f1208103a41bccc4754f15a9366f49b676", [:mix], [{:hackney, "~> 1.6.3", [hex: :hackney, optional: false]}]},
   "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},