Multi-lang alternate tags: missing rel="alternate"

[Wannes Debusschere]

The plugin outputs the hreflang tags without the rel="alternate"

<link href="https://www.mysite.com/en" hreflang="en">
<link href="https://www.mysite.com/fr" hreflang="fr">
<link href="https://www.mysite.com/nl" hreflang="nl">
<link href="https://lwww.mysite.com/en" hreflang="x-default">

'rel' => 'alternate',code is missing 2 times in site/plugins/kirby-seo/classes/Meta.php

More info
https://developers.google.com/search/docs/specialty/international/localized-versions