Changelog: add Linux CVEs.

debian/changelog

@@ -8,7 +8,9 @@ tails (3.12) UNRELEASED; urgency=medium
       On first boot, grow the system partition to a size that's a factor
       of the size of the boot medium and randomize GUIDs (Closes: #15319).
     - Upgrade Linux to 4.19, version 4.19.13-1 (Closes: #16073, #16224).
-      XXX: CVEs 4.18.20-2..4.19.13-1
+      Fixes CVE-2018-19985, CVE-2018-19406, CVE-2018-16862, CVE-2018-18397,
+      CVE-2018-18397, CVE-2018-18397, CVE-2018-18397, CVE-2018-19824,
+      CVE-2018-14625.
     - Remove Liferea (Closes: #11082, #15776).
     - Upgrade to the Debian Stretch 9.6 point-release.