Allow public_suffix v7

https://github.com/weppos/publicsuffix-ruby/blob/55affc6d5562b9a3cc34aeea3c535d4c236500d9/CHANGELOG.md#700

Author: dentarg

twingly-url.gemspec

@@ -15,7 +15,7 @@ Gem::Specification.new do |s|
   s.required_ruby_version = ">= 2.6"
 
   s.add_dependency "addressable", "~> 2.6"
-  s.add_dependency "public_suffix", ">= 3.0.1", "< 6.0"
+  s.add_dependency "public_suffix", ">= 3.0.1", "< 8"
 
   s.add_development_dependency "rake", "~> 12"
   s.add_development_dependency "rspec", "~> 3"