(GH-372) Reset min Ruby requirement

Prior to this change the required Ruby version was set to greater than
or equal to 2.7. This meant that the spec_helpers gem would not run on
systems with Ruby 2.5.

This change updates the required Ruby version so that Rubies 2.5 and
above are compatibel.

Additionally the following gems were downgraded for compatibility:

* pathspec is now ~> 0.2
* puppet-lint is now ~> 2.5.2

Gemfile

@@ -25,7 +25,7 @@ group :development do
   gem 'rubocop', '~> 1.6.1', require: false
   gem 'rubocop-rspec', '~> 2.0.1', require: false
   gem 'rubocop-performance', '~> 1.9.1', require: false
-
+  #
   gem 'fakefs'
   gem 'yard'
 end

puppetlabs_spec_helper.gemspec

@@ -26,11 +26,11 @@ Gem::Specification.new do |spec|
   spec.executables = Dir['bin/**/*'].map { |f| File.basename(f) }
   spec.require_paths = ['lib']
 
-  spec.required_ruby_version = Gem::Requirement.new('>= 2.7')
+  spec.required_ruby_version = Gem::Requirement.new('>= 2.5')
 
   spec.add_runtime_dependency 'mocha', '~> 1.0'
-  spec.add_runtime_dependency 'pathspec', '~> 1.0'
-  spec.add_runtime_dependency 'puppet-lint', '~> 3.0'
+  spec.add_runtime_dependency 'pathspec', '~> 0.2'
+  spec.add_runtime_dependency 'puppet-lint', '~> 2.5.2'
   spec.add_runtime_dependency 'puppet-syntax', '~> 3.0'
   spec.add_runtime_dependency 'rspec-github', '~> 2.0'
   spec.add_runtime_dependency 'rspec-puppet', '~> 2.0'