Add entries for updated packages to the changelog for 1.8.1.

debian/changelog

@@ -2,7 +2,9 @@ tails (1.8.1) unstable; urgency=medium
 
   * Security fixes
     - Upgrade Tor Browser to 5.0.6.
-    - XXX: packages (Linux?)
+    - Upgrade Linux to 3.16.7-ckt20-1+deb8u1
+    - Upgrade gdkpixbuf to 2.26.1-1+deb7u3
+    - Upgrade bind9 tools to 1:9.8.4.dfsg.P1-6+nmu2+deb7u8
 
   * Bugfixes
     - Fix time synchronization in bridge mode by refreshing our patch