Bump excoveralls from 0.10.3 to 0.10.4 (#63)

Bumps [excoveralls](https://github.com/parroty/excoveralls) from 0.10.3 to 0.10.4.
- [Release notes](https://github.com/parroty/excoveralls/releases)
- [Changelog](https://github.com/parroty/excoveralls/blob/master/CHANGELOG.md)
- [Commits](parroty/excoveralls@v0.10.3...v0.10.4)

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

mix.lock

@@ -7,9 +7,9 @@
   "earmark": {:hex, :earmark, "1.3.1", "73812f447f7a42358d3ba79283cfa3075a7580a3a2ed457616d6517ac3738cb9", [:mix], [], "hexpm"},
   "ecto": {:hex, :ecto, "3.0.6", "d33ab5b3f7553a41507d4b0ad5bf192d533119c4ad08f3a5d63d85aa12117dc9", [:mix], [{:decimal, "~> 1.6", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:poison, "~> 2.2 or ~> 3.0", [hex: :poison, repo: "hexpm", optional: true]}], "hexpm"},
   "ex_doc": {:hex, :ex_doc, "0.19.2", "6f4081ccd9ed081b6dc0bd5af97a41e87f5554de469e7d76025fba535180565f", [:mix], [{:earmark, "~> 1.2", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.10", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
-  "excoveralls": {:hex, :excoveralls, "0.10.3", "b090a3fbcb3cfa136f0427d038c92a9051f840953ec11b40ee74d9d4eac04d1e", [:mix], [{:hackney, "~> 1.13", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "excoveralls": {:hex, :excoveralls, "0.10.4", "b86230f0978bbc630c139af5066af7cd74fd16536f71bc047d1037091f9f63a9", [:mix], [{:hackney, "~> 1.13", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
   "exjsx": {:hex, :exjsx, "4.0.0", "60548841e0212df401e38e63c0078ec57b33e7ea49b032c796ccad8cde794b5c", [:mix], [{:jsx, "~> 2.8.0", [hex: :jsx, repo: "hexpm", optional: false]}], "hexpm"},
-  "hackney": {:hex, :hackney, "1.14.3", "b5f6f5dcc4f1fba340762738759209e21914516df6be440d85772542d4a5e412", [:rebar3], [{:certifi, "2.4.2", [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, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
+  "hackney": {:hex, :hackney, "1.15.0", "287a5d2304d516f63e56c469511c42b016423bcb167e61b611f6bad47e3ca60e", [:rebar3], [{:certifi, "2.4.2", [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, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [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"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
   "jsx": {:hex, :jsx, "2.8.3", "a05252d381885240744d955fbe3cf810504eb2567164824e19303ea59eef62cf", [:mix, :rebar3], [], "hexpm"},