Change RSS generation.

See https://discourse.gohugo.io/t/site-vs-site-vs-site/49252 and
b6df155eb8
and https://github.com/adityatelange/hugo-PaperMod/issues/1839

layouts/_default/rss.xml

@@ -9,14 +9,14 @@
     <language>{{.}}</language>
     {{end}}
 
-    {{ with .Site.Author.email }}
+    {{ with site.Params.author.email  }}
     <managingEditor>
-        {{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}
+        {{.}}{{ with $ site.Params.author.name }} ({{.}}){{end}}
     </managingEditor>
     {{end}}
 
-    {{ with .Site.Author.email }}
+    {{ with site.Params.author.email  }}
-    <webMaster>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}</webMaster>
+    <webMaster>{{.}}{{ with $ site.Params.author.name }} ({{.}}){{end}}</webMaster>
     {{end}}
 
     {{ with .Site.Copyright }}
@@ -39,7 +39,7 @@
 
       <link>{{ .Permalink }}</link>
       <pubDate>{{ .Date.Format "Mon, 02 Jan 2006 15:04:05 -0700" | safeHTML }}</pubDate>
-      {{ with .Site.Author.email }}<author>{{.}}{{ with $.Site.Author.name }} ({{.}}){{end}}</author>{{end}}
+      {{ with site.Params.author.email  }}<author>{{.}}{{ with $ site.Params.author.name }} ({{.}}){{end}}</author>{{end}}
       <guid>{{ .Permalink }}</guid>
       <description>
           {{ .Content | html }}