Update debian/changelog

UNRELEASED --> beowulf
Closing BTS bug 505

debian/changelog

@@ -1,6 +1,6 @@
-iwd (0.14-2+devuan1~beowulf1) UNRELEASED; urgency=medium
+iwd (0.14-2+devuan1~beowulf1) beowulf; urgency=medium
 
-  * Target beowulf.
+  * Target beowulf. (Closes #505)
 
  -- Job Bautista <jobbautista9@protonmail.com>  Sun, 09 Aug 2020 16:02:20 +0800