Nofollow feature request

Hi, Thanks for good plugin.
Can you make it a bit more useful?

The problem:

Yoast place to the sitemaps SEO links for (not for webmaster – but for YOAST web) like sitemap_index.xml, visible to the browser and to search engines:

XML Sitemap
Generated by YoastSEO, this is an XML Sitemap, meant for consumption by search engines.
You can find more information about XML sitemaps on sitemaps.org.

<a href="https://yoa.st/1y5" target="_blank" rel="noopener noreferrer">Yoast</a>
<a href="https://yoa.st/1y6" target="_blank" rel="noopener noreferrer">SEO</a>
<a href="https://sitemaps.org" target="_blank" rel="noopener noreferrer">sitemaps.org</a>

So there are 3 links on EACH sitemap. And all the webmasters giving the ‘present’ to YOAST as some SEO weight.

Solution:
Tweak to add nofollow parameter to the rel attribute of all those links:

rel=”nofollow noopener noreferrer”