Bump credo from 1.5.5 to 1.5.6

Bumps [credo](https://github.com/rrrene/credo) from 1.5.5 to 1.5.6.
- [Release notes](https://github.com/rrrene/credo/releases)
- [Changelog](https://github.com/rrrene/credo/blob/v1.5.6/CHANGELOG.md)
- [Commits](rrrene/credo@v1.5.5...v1.5.6)

---
updated-dependencies:
- dependency-name: credo
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

mix.lock

@@ -1,7 +1,7 @@
 %{
   "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"},
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm", "4a0850c9be22a43af9920a71ab17c051f5f7d45c209e40269a1938832510e4d9"},
-  "credo": {:hex, :credo, "1.5.5", "e8f422026f553bc3bebb81c8e8bf1932f498ca03339856c7fec63d3faac8424b", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "dd8623ab7091956a855dc9f3062486add9c52d310dfd62748779c4315d8247de"},
+  "credo": {:hex, :credo, "1.5.6", "e04cc0fdc236fefbb578e0c04bd01a471081616e741d386909e527ac146016c6", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "4b52a3e558bd64e30de62a648518a5ea2b6e3e5d2b164ef5296244753fc7eb17"},
   "db_connection": {:hex, :db_connection, "2.3.0", "d56ef906956a37959bcb385704fc04035f4f43c0f560dd23e00740daf8028c49", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm", "dcc082b8f723de9a630451b49fdbd7a59b065c4b38176fb147aaf773574d4520"},
   "decimal": {:hex, :decimal, "2.0.0", "a78296e617b0f5dd4c6caf57c714431347912ffb1d0842e998e9792b5642d697", [:mix], [], "hexpm", "34666e9c55dea81013e77d9d87370fe6cb6291d1ef32f46a1600230b1d44f577"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.13", "0c98163e7d04a15feb62000e1a891489feb29f3d10cb57d4f845c405852bbef8", [:mix], [], "hexpm", "d602c26af3a0af43d2f2645613f65841657ad6efc9f0e361c3b6c06b578214ba"},