Alter to require ruby 3 or higher to use the gem

We chose to update a minor version rather than patch to make sure 1.6.0 can still be used for projects that are not yet in Ruby 3 and need to alter rules.

mavenlint.gemspec

@@ -2,7 +2,7 @@
 
 Gem::Specification.new do |s|
   s.name        = 'mavenlint'
-  s.version     = '1.6.0'
+  s.version     = '1.7.0'
   s.licenses    = ['MIT']
   s.summary     = 'Mavenlink Rubocop config'
   s.authors     = ['Mavenlink']
@@ -14,5 +14,5 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec', '3.12'
   s.add_development_dependency 'rubocop', '1.31'
 
-  s.required_ruby_version = '>= 2.7.5'
+  s.required_ruby_version = '>= 3.0.0'
 end