Bump parallel_tests from 3.3.0 to 3.4.0 in /Library/Homebrew

Bumps [parallel_tests](https://github.com/grosser/parallel_tests) from 3.3.0 to 3.4.0.
- [Release notes](https://github.com/grosser/parallel_tests/releases)
- [Changelog](https://github.com/grosser/parallel_tests/blob/master/CHANGELOG.md)
- [Commits](https://github.com/grosser/parallel_tests/compare/v3.3.0...v3.4.0

)

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

Library/Homebrew/Gemfile.lock

@@ -54,8 +54,8 @@ GEM
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
     ntlm-http (0.1.1)
-    parallel (1.20.0)
-    parallel_tests (3.3.0)
+    parallel (1.20.1)
+    parallel_tests (3.4.0)
       parallel
     parlour (4.0.1)
       commander (~> 4.5)