Merge branch '1149-fix-rss-feed-header' into 'development'

Resolve "Fix rss feed header"

Closes #1149

See merge request !1908

resources/views/resultpages/metager3resultsrss20.blade.php

-<?xmlversion = "1.0"encoding = "UTF-8"?>
+<?xml version="1.0" encoding="UTF-8"?>
  <rss version="2.0"
       xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/"
       xmlns:mg="http://metager.de/opensearch/"