Bump credo from 1.1.0 to 1.2.1 (#138)

Bumps [credo](https://github.com/rrrene/credo) from 1.1.0 to 1.2.1.
- [Release notes](https://github.com/rrrene/credo/releases)
- [Changelog](https://github.com/rrrene/credo/blob/master/CHANGELOG.md)
- [Commits](rrrene/credo@v1.1.0...v1.2.1)

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

Author: dependabot-preview[bot]

mix.lock

@@ -3,7 +3,7 @@
   "amqp_client": {:hex, :amqp_client, "3.7.15", "99c46aad3406199f9aec95356f43fa73f28af2fc9da1de5b601367231e37992c", [:make, :rebar3], [{:rabbit_common, "3.7.15", [hex: :rabbit_common, repo: "hexpm", optional: false]}], "hexpm"},
   "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm"},
   "certifi": {:hex, :certifi, "2.5.1", "867ce347f7c7d78563450a18a6a28a8090331e77fa02380b4a21962a65d36ee5", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
-  "credo": {:hex, :credo, "1.1.0", "e0c07b2fd7e2109495f582430a1bc96b2c71b7d94c59dfad120529f65f19872f", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "credo": {:hex, :credo, "1.2.1", "6d8e07b31e3937b669e19add0076ee9bd7268cf433878209b631fe38110ea94a", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "dialyxir": {:hex, :dialyxir, "1.0.0-rc.7", "6287f8f2cb45df8584317a4be1075b8c9b8a69de8eeb82b4d9e6c761cf2664cd", [:mix], [{:erlex, ">= 0.2.5", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
   "earmark": {:hex, :earmark, "1.4.3", "364ca2e9710f6bff494117dbbd53880d84bebb692dafc3a78eb50aa3183f2bfd", [:mix], [], "hexpm"},
   "erlex": {:hex, :erlex, "0.2.5", "e51132f2f472e13d606d808f0574508eeea2030d487fc002b46ad97e738b0510", [:mix], [], "hexpm"},