Use full month name for post date

When `lastmod` is specified, a post would indicate that it was updated, but it incorrectly used the original date instead of the modification date.

i18n/en.toml

@@ -13,7 +13,7 @@ other = "Jan 2, 2006"
 [post]
 
 [post.created]
-other = "Jan 2, 2006"
+other = "January 2, 2006"
 
 [post.updated]
-other = "Updated Jan 2, 2006"
+other = "Updated January 2, 2006"

layouts/_default/single.html

@@ -7,7 +7,7 @@
             {{ if eq .Lastmod .Date }}
                 <time>{{ .Date | time.Format (i18n "post.created") }}</time>
             {{ else }}
-                <time>{{ .Date | time.Format (i18n "post.updated") }}</time>
+                <time>{{ .Lastmod | time.Format (i18n "post.updated") }}</time>
             {{ end }}
         {{- end -}}
         </div>