authors, not author for posts metadata

Author: agriyakhetarpal

layouts/partials/posts/meta.html

@@ -1,6 +1,9 @@
+{{- if .Params.Author -}}
+  {{- errorf "Page %q uses deprecated 'author' field. Please use 'authors' instead." .File.Path -}}
+{{- end -}}
 <div class="post-meta">
 <span class="post-authors">
-    {{- range .Params.author -}}
+    {{- range .Params.Authors -}}
     {{ $author := trim (index (findRE `[^<]*` . 1) 0) "\n\r " }}
     {{ $handle := index (index (findRESubmatch `<(.*?)>` . 1) 0) 1 }}
     <div class="post-author">

layouts/partials/section/section.html

@@ -9,6 +9,9 @@ <h5 class="subtitle">{{ .Params.Subtitle }}</h5>
   {{ .Content }}
   {{ else }}
   {{ range .Pages }}
+  {{- if .Params.Author -}}
+    {{- errorf "Page %q uses deprecated 'author' field. Please use 'authors' instead." .File.Path -}}
+  {{- end -}}
   <div class="post-list">
     <article>
       <div class="post-title"><a href="{{ .RelPermalink }}">{{ .Title }}</a></div>