Update gemspec format

radius.gemspec

@@ -2,14 +2,15 @@
 
 require File.join(File.dirname(__FILE__), 'lib', 'radius', 'version')
 Gem::Specification.new do |s|
-  s.name = %q{radius}
+  s.name = "radius"
   s.version = ::Radius.version
   s.licenses = ["MIT"]
 
-  s.required_rubygems_version = Gem::Requirement.new("> 1.3.1") if s.respond_to? :required_rubygems_version=
-  s.authors = [%q{John W. Long ([email protected])}, %q{David Chelimsky ([email protected])}, %q{Bryce Kerley ([email protected])}]
+  s.required_ruby_version = ">= 2.6.0"
+
+  s.authors = ["John W. Long", "David Chelimsky", "Bryce Kerley"]
   s.description = %q{Radius is a powerful tag-based template language for Ruby inspired by the template languages used in MovableType and TextPattern. It uses tags similar to XML, but can be used to generate any form of plain text (HTML, e-mail, etc...).}
-  s.email = %q{[email protected]}
+  s.email = ["[email protected]", "[email protected]", "[email protected]"]
   s.extra_rdoc_files = [
     "CHANGELOG",
     "CONTRIBUTORS",
@@ -23,5 +24,12 @@ Gem::Specification.new do |s|
 
   s.homepage = %q{http://github.com/jlong/radius}
   s.summary = %q{A tag-based templating language for Ruby.}
+
+  s.metadata = {
+    "homepage_uri" => "https://github.com/jlong/radius",
+    "source_code_uri" => "https://github.com/jlong/radius",
+    "changelog_uri" => "https://github.com/jlong/radius/blob/master/CHANGELOG",
+    "bug_tracker_uri" => "https://github.com/jlong/radius/issues"
+  }
 end