Adds missing spec files

app/finders/users/yoast_seo_author_sitemap.rb

@@ -0,0 +1,34 @@
+module WPScan
+  module Finders
+    module Users
+      # The YOAST SEO plugin has an author-sitemap.xml which can leak usernames
+      # See https://github.com/wpscanteam/wpscan/issues/1228
+      class YoastSeoAuthorSitemap < CMSScanner::Finders::Finder
+        # @param [ Hash ] opts
+        #
+        # @return [ Array<User> ]
+        def aggressive(_opts = {})
+          found = []
+
+          Browser.get(sitemap_url).html.xpath('//url/loc').each do |user_tag|
+            username = user_tag.text.to_s[%r{/author/([^\/]+)/}, 1]
+
+            next unless username && !username.strip.empty?
+
+            found << CMSScanner::User.new(username,
+                                          found_by: found_by,
+                                          confidence: 100,
+                                          interesting_entries: [sitemap_url])
+          end
+
+          found
+        end
+
+        # @return [ String ] The URL of the author-sitemap
+        def sitemap_url
+          @sitemap_url ||= target.url('author-sitemap.xml')
+        end
+      end
+    end
+  end
+end