Update puppetlabs_spec_helper requirement from ~> 6.0 to ~> 7.2

Updates the requirements on [puppetlabs_spec_helper](https://github.com/puppetlabs/puppetlabs_spec_helper) to permit the latest version.
- [Release notes](https://github.com/puppetlabs/puppetlabs_spec_helper/releases)
- [Changelog](https://github.com/puppetlabs/puppetlabs_spec_helper/blob/main/CHANGELOG.md)
- [Commits](puppetlabs/puppetlabs_spec_helper@v6.0.0...v7.2.0)

---
updated-dependencies:
- dependency-name: puppetlabs_spec_helper
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -23,7 +23,7 @@ group :development do
   gem "voxpupuli-puppet-lint-plugins", '~> 5.0', require: false
   gem "facterdb", '~> 1.18',                     require: false
   gem "metadata-json-lint", '~> 3.0',            require: false
-  gem "puppetlabs_spec_helper", '~> 6.0',        require: false
+  gem "puppetlabs_spec_helper", '~> 7.2',        require: false
   gem "rspec-puppet-facts", '~> 2.0',            require: false
   gem "dependency_checker", '~> 1.0.0',          require: false
   gem "parallel_tests", '= 3.12.1',              require: false