build(deps): bump codecov from 0.2.12 to 0.2.15 in /Library/Homebrew

Bumps [codecov](https://github.com/codecov/codecov-ruby) from 0.2.12 to 0.2.15.
- [Release notes](https://github.com/codecov/codecov-ruby/releases)
- [Changelog](https://github.com/codecov/codecov-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-ruby/compare/v0.2.12...v0.2.15)

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

Library/Homebrew/Gemfile.lock

@@ -10,9 +10,8 @@ GEM
     ast (2.4.1)
     bindata (2.4.8)
     byebug (11.1.3)
-    codecov (0.2.12)
-      json
-      simplecov
+    codecov (0.2.15)
+      simplecov (>= 0.15, < 0.21)
     coderay (1.1.3)
     colorize (0.8.1)
     commander (4.5.2)
@@ -20,7 +19,7 @@ GEM
     concurrent-ruby (1.1.7)
     connection_pool (2.2.3)
     diff-lcs (1.4.4)
-    docile (1.3.2)
+    docile (1.3.4)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
     elftools (1.1.3)
@@ -31,7 +30,6 @@ GEM
       domain_name (~> 0.5)
     i18n (1.8.5)
       concurrent-ruby (~> 1.0)
-    json (2.3.1)
     mechanize (2.7.6)
       domain_name (~> 0.5, >= 0.5.1)
       http-cookie (~> 1.0)