Make it compatible with old versions of Ruby

Author: pitbulk

lib/onelogin/ruby-saml/attributes.rb

@@ -124,7 +124,11 @@ def ==(other)
       def fetch(name)
         attributes.each_key do |attribute_key|
           if name.is_a?(Regexp)
-            return self[attribute_key] if name.match?(attribute_key)
+            if name.method_exists? :match?
+              return self[attribute_key] if name.match?(attribute_key)
+            else 
+              return self[attribute_key] if name.match(attribute_key)
+            end
           elsif canonize_name(name) == canonize_name(attribute_key)
             return self[attribute_key]
           end

test/attributes_test.rb

@@ -22,6 +22,8 @@ class AttributesTest < Minitest::Test
 
     it 'fetches regexp attribute' do
       assert_equal('Tom', attributes.fetch(/givenname/))
+      assert_equal('Tom', attributes.fetch(/gi(.*)/))
+      assert_nil(attributes.fetch(/^z.*/))
       assert_equal('Hanks', attributes.fetch(/surname/))
     end
   end