Bump parallel_tests from 3.5.0 to 3.5.1 (#15853)

Bumps [parallel_tests](https://github.com/grosser/parallel_tests) from 3.5.0 to 3.5.1.
- [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/v3.5.0...v3.5.1)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -400,7 +400,7 @@ GEM
       av (~> 0.9.0)
       paperclip (>= 2.5.2)
     parallel (1.20.1)
-    parallel_tests (3.5.0)
+    parallel_tests (3.5.1)
       parallel
     parser (3.0.0.0)
       ast (~> 2.4.1)