Add author name by default to RSS feeds

data/templates/rss-item.xml

@@ -4,4 +4,5 @@
     <description><![CDATA[$description$]]></description>
     <pubDate>$published$</pubDate>
     <guid>$root$$url$</guid>
+    <dc:creator>$authorName$</dc:creator>
 </item>

data/templates/rss.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
-<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
+<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"
+    xmlns:dc="http://purl.org/dc/elements/1.1/">
     <channel>
         <title>$title$</title>
         <link>$root$</link>

src/Hakyll/Web/Feed.hs

@@ -77,6 +77,8 @@ renderFeed feedPath itemPath config itemContext items = do
 
     itemContext' = mconcat
         [ constField "root" (feedRoot config)
+        , constField "authorName"  (feedAuthorName config)
+        , constField "authorEmail" (feedAuthorEmail config)
         , itemContext
         ]