build(deps-dev): bump parallel_tests from 3.3.0 to 3.4.0

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](grosser/parallel_tests@v3.3.0...v3.4.0)

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

Author: dependabot[bot]

Gemfile.lock

@@ -307,8 +307,8 @@ GEM
       mini_portile2 (~> 2.4.0)
     os (1.0.1)
     palm_civet (1.1.0)
-    parallel (1.19.2)
-    parallel_tests (3.3.0)
+    parallel (1.20.1)
+    parallel_tests (3.4.0)
       parallel
     parser (2.7.2.0)
       ast (~> 2.4.1)