Bump credo from 1.6.3 to 1.6.4

Bumps [credo](https://github.com/rrrene/credo) from 1.6.3 to 1.6.4.
- [Release notes](https://github.com/rrrene/credo/releases)
- [Changelog](https://github.com/rrrene/credo/blob/master/CHANGELOG.md)
- [Commits](rrrene/credo@v1.6.3...v1.6.4)

---
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

@@ -2,7 +2,7 @@
   "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"},
   "certifi": {:hex, :certifi, "2.9.0", "6f2a475689dd47f19fb74334859d460a2dc4e3252a3324bd2111b8f0429e7e21", [:rebar3], [], "hexpm", "266da46bdb06d6c6d35fde799bcb28d36d985d424ad7c08b5bb48f5b5cdd4641"},
   "codepagex": {:hex, :codepagex, "0.1.4", "dae3bc57e9334c324914b32ed61c0a30929fac3e73dc71fc611ed7eeb2dcb867", [:mix], [], "hexpm"},
-  "credo": {:hex, :credo, "1.6.3", "0a9f8925dbc8f940031b789f4623fc9a0eea99d3eed600fe831e403eb96c6a83", [: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", "1167cde00e6661d740fc54da2ee268e35d3982f027399b64d3e2e83af57a1180"},
+  "credo": {:hex, :credo, "1.6.4", "ddd474afb6e8c240313f3a7b0d025cc3213f0d171879429bf8535d7021d9ad78", [: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", "c28f910b61e1ff829bffa056ef7293a8db50e87f2c57a9b5c3f57eee124536b7"},
   "dialyxir": {:hex, :dialyxir, "1.1.0", "c5aab0d6e71e5522e77beff7ba9e08f8e02bad90dfbeffae60eaf0cb47e29488", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "07ea8e49c45f15264ebe6d5b93799d4dd56a44036cf42d0ad9c960bc266c0b9a"},
   "earmark": {:hex, :earmark, "1.4.4", "4821b8d05cda507189d51f2caeef370cf1e18ca5d7dfb7d31e9cafe6688106a4", [:mix], [], "hexpm", "1f93aba7340574847c0f609da787f0d79efcab51b044bb6e242cae5aca9d264d"},
   "earmark_parser": {:hex, :earmark_parser, "1.4.20", "89970db71b11b6b89759ce16807e857df154f8df3e807b2920a8c39834a9e5cf", [:mix], [], "hexpm", "1eb0d2dabeeeff200e0d17dc3048a6045aab271f73ebb82e416464832eb57bdd"},