Include matrix gem in gemspec for Ruby 3.1+

prawn-svg.gemspec

@@ -1,27 +1,28 @@
-# -*- encoding: utf-8 -*-
-require File.expand_path('../lib/prawn/svg/version', __FILE__)
+require File.expand_path('lib/prawn/svg/version', __dir__)
 
 Gem::Specification.new do |gem|
   gem.name = 'prawn-svg'
   gem.version = Prawn::SVG::VERSION
-  gem.summary = "SVG renderer for Prawn PDF library"
-  gem.description = "This gem allows you to render SVG directly into a PDF using the 'prawn' gem.  Since PDF is vector-based, you'll get nice scaled graphics if you use SVG instead of an image."
-  gem.author = "Roger Nesbitt"
-  gem.email = "[email protected]"
-  gem.homepage = "http://github.com/mogest/prawn-svg"
+  gem.summary = 'SVG renderer for Prawn PDF library'
+  gem.description = <<-EOT.strip
+    This gem allows you to render SVG directly into a PDF using the 'prawn' gem.  Since PDF is vector-based, you'll get nice scaled graphics if you use SVG instead of an image.
+  EOT
+  gem.author = 'Mog Nesbitt'
+  gem.email = '[email protected]'
+  gem.homepage = 'http://github.com/mogest/prawn-svg'
   gem.license = 'MIT'
 
-  gem.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
+  gem.executables   = `git ls-files -- bin/*`.split("\n").map { |f| File.basename(f) }
   gem.files         = `git ls-files`.split("\n")
   gem.test_files    = `git ls-files -- {test,spec,features}/*`.split("\n")
-  gem.name          = "prawn-svg"
-  gem.require_paths = ["lib"]
+  gem.require_paths = ['lib']
 
   gem.required_ruby_version = '>= 2.3.0'
 
-  gem.add_runtime_dependency "prawn", ">= 0.11.1", "< 3"
-  gem.add_runtime_dependency "css_parser", "~> 1.6"
-  gem.add_runtime_dependency "rexml", "~> 3.2"
-  gem.add_development_dependency "rspec", "~> 3.0"
-  gem.add_development_dependency "rake", "~> 13.0"
+  gem.add_runtime_dependency 'css_parser', '~> 1.6'
+  gem.add_runtime_dependency 'matrix', '~> 0.4.2'
+  gem.add_runtime_dependency 'prawn', '>= 0.11.1', '< 3'
+  gem.add_runtime_dependency 'rexml', '~> 3.2'
+  gem.add_development_dependency 'rake', '~> 13.0'
+  gem.add_development_dependency 'rspec', '~> 3.0'
 end