Fix posts/index.xml RSS feed generation with Hugo v0.153.0

Author: Leo3418

content/en/posts/_index.md

@@ -0,0 +1,9 @@
+---
+# This file is necessary since Hugo v0.153.0 to generate posts/index.{html,xml}
+# like older Hugo versions would.  To be more specific, a Git bisect session
+# pointed to Hugo commit 264022a75a8e4d91d7461747eef4d06267cc519f as the change
+# that made this file necessary.  The exact cause of why this file is necessary
+# is still unclear because that commit is unfortunately a very big one tangling
+# 13,654 insertions and 5,907 deletions, not following the best Git practices.
+title: "Posts"
+---