Update rspec_junit_formatter requirement from ~> 0.4.1 to ~> 0.6.0

Updates the requirements on [rspec_junit_formatter](https://github.com/sj26/rspec_junit_formatter) to permit the latest version.
- [Release notes](https://github.com/sj26/rspec_junit_formatter/releases)
- [Changelog](https://github.com/sj26/rspec_junit_formatter/blob/main/CHANGELOG.md)
- [Commits](sj26/rspec_junit_formatter@v0.4.1...v0.6.0)

---
updated-dependencies:
- dependency-name: rspec_junit_formatter
  dependency-type: direct:production
...

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

Gemfile

@@ -10,6 +10,6 @@ gem "activesupport", ">= 4.2", "< 7"
 gem "gc_ruboconfig", "~> 5.0"
 gem "rake", "~> 13.0"
 gem "rspec", "~> 3.5"
-gem "rspec_junit_formatter", "~> 0.4.1"
+gem "rspec_junit_formatter", "~> 0.6.0"
 gem "timecop", "~> 0.8"
 gem "webmock", "~> 3.0"