Bump excoveralls from 0.12.1 to 0.12.2 (#139)

Bumps [excoveralls](https://github.com/parroty/excoveralls) from 0.12.1 to 0.12.2.
- [Release notes](https://github.com/parroty/excoveralls/releases)
- [Changelog](https://github.com/parroty/excoveralls/blob/master/CHANGELOG.md)
- [Commits](parroty/excoveralls@v0.12.1...v0.12.2)

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

Author: dependabot-preview[bot]

mix.lock

@@ -8,7 +8,7 @@
   "earmark": {:hex, :earmark, "1.4.3", "364ca2e9710f6bff494117dbbd53880d84bebb692dafc3a78eb50aa3183f2bfd", [:mix], [], "hexpm"},
   "erlex": {:hex, :erlex, "0.2.5", "e51132f2f472e13d606d808f0574508eeea2030d487fc002b46ad97e738b0510", [:mix], [], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.21.3", "857ec876b35a587c5d9148a2512e952e24c24345552259464b98bfbb883c7b42", [:mix], [{:earmark, "~> 1.4", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
-  "excoveralls": {:hex, :excoveralls, "0.12.1", "a553c59f6850d0aff3770e4729515762ba7c8e41eedde03208182a8dc9d0ce07", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "excoveralls": {:hex, :excoveralls, "0.12.2", "a513defac45c59e310ac42fcf2b8ae96f1f85746410f30b1ff2b710a4b6cd44b", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "goldrush": {:hex, :goldrush, "0.1.9", "f06e5d5f1277da5c413e84d5a2924174182fb108dabb39d5ec548b27424cd106", [:rebar3], [], "hexpm"},
   "hackney": {:hex, :hackney, "1.15.2", "07e33c794f8f8964ee86cebec1a8ed88db5070e52e904b8f12209773c1036085", [: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, "1.1.5", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
   "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},