Fixes paginator issue since hugo v0.123.0

Pages of kind "page" don't allow the creation of a paginator (.Paginate
or .Paginator) in the newest version of hugo.
Pages of kind "section" (e.g. /posts) still allow the creation. This fix
adds a check for the kind of page and excludes pages with kind "page"
from creating a paginator.

layouts/partials/meta/post.html

@@ -2,6 +2,7 @@
 {{ if eq .Section "posts" }}
     {{ $ISO_date := dateFormat "2006-01-02T15:04:05Z0700" .Date | safeHTML }}
     <!-- Pagination meta tags for list pages only -->
+    {{ if ne .Page.Kind "page" }}
     {{ $paginator := .Paginate (where .Pages "Section" "blog") }}
     {{ if $paginator }}
     <link rel="first" href="{{ $paginator.First.URL }}" />
@@ -13,6 +14,7 @@
     <link rel="next" href="{{ $paginator.Next.URL }}" />
     {{end }}
     {{end }}
+    {{end }}
 
     <meta property="og:type" content="article" />
     <meta property="og:article:published_time" content={{ $ISO_date | safeHTML }} />