Bump excoveralls from 0.17.0 to 0.18.0

Bumps [excoveralls](https://github.com/parroty/excoveralls) from 0.17.0 to 0.18.0.
- [Release notes](https://github.com/parroty/excoveralls/releases)
- [Changelog](https://github.com/parroty/excoveralls/blob/master/CHANGELOG.md)
- [Commits](parroty/excoveralls@v0.17.0...v0.18.0)

---
updated-dependencies:
- dependency-name: excoveralls
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

mix.exs

@@ -55,7 +55,7 @@ defmodule Fields.MixProject do
       # stream_data for property based testing
       {:stream_data, "~> 0.6.0", only: :test},
       # tracking test coverage
-      {:excoveralls, "~> 0.17.0", only: [:test, :dev]},
+      {:excoveralls, "~> 0.18.0", only: [:test, :dev]},
 
       # documentation
       {:ex_doc, "~> 0.30.3", only: :dev},

mix.lock

@@ -9,7 +9,7 @@
   "elixir_make": {:hex, :elixir_make, "0.7.7", "7128c60c2476019ed978210c245badf08b03dbec4f24d05790ef791da11aa17c", [:mix], [{:castore, "~> 0.1 or ~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}], "hexpm", "5bc19fff950fad52bbe5f211b12db9ec82c6b34a9647da0c2224b8b8464c7e6c"},
   "envar": {:hex, :envar, "1.1.0", "105bcac5a03800a1eb21e2c7e229edc687359b0cc184150ec1380db5928c115c", [:mix], [], "hexpm", "97028ab4a040a5c19e613fdf46a41cf51c6e848d99077e525b338e21d2993320"},
   "ex_doc": {:hex, :ex_doc, "0.30.3", "bfca4d340e3b95f2eb26e72e4890da83e2b3a5c5b0e52607333bf5017284b063", [:mix], [{:earmark_parser, "~> 1.4.31", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "fbc8702046c1d25edf79de376297e608ac78cdc3a29f075484773ad1718918b6"},
-  "excoveralls": {:hex, :excoveralls, "0.17.0", "279f124dba347903bb654bc40745c493ae265d45040001b4899ea1edf88078c7", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "08b638d114387a888f9cb8d65f2a0021ec04c3e447b793efa7c1e734aba93004"},
+  "excoveralls": {:hex, :excoveralls, "0.18.0", "b92497e69465dc51bc37a6422226ee690ab437e4c06877e836f1c18daeb35da9", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "1109bb911f3cb583401760be49c02cbbd16aed66ea9509fc5479335d284da60b"},
   "hackney": {:hex, :hackney, "1.18.1", "f48bf88f521f2a229fc7bae88cf4f85adc9cd9bcf23b5dc8eb6a1788c662c4f6", [:rebar3], [{:certifi, "~>2.9.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~>6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~>1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.3.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~>1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "a4ecdaff44297e9b5894ae499e9a070ea1888c84afdd1fd9b7b2bc384950128e"},
   "html_sanitize_ex": {:hex, :html_sanitize_ex, "1.4.3", "67b3d9fa8691b727317e0cc96b9b3093be00ee45419ffb221cdeee88e75d1360", [:mix], [{:mochiweb, "~> 2.15 or ~> 3.1", [hex: :mochiweb, repo: "hexpm", optional: false]}], "hexpm", "87748d3c4afe949c7c6eb7150c958c2bcba43fc5b2a02686af30e636b74bccb7"},
   "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},