Document changes and release 1:78.8.0-1

debian/changelog

+thunderbird (1:78.8.0-1) unstable; urgency=medium
+
+  [ Pino Toscano ]
+  * [f2f1f3f] thunderbird: Stop shipping /u/s/p/thunderbird.png symlink
+
+  [ Carsten Schoenert ]
+  * [f5707a7] New upstream version 78.8.0
+    Fixed CVE issues in upstream version 78.8 (MFSA 2021-09):
+    CVE-2021-23969: Content Security Policy violation report could have
+                    contained the destination of a redirect
+    CVE-2021-23968: Content Security Policy violation report could have
+                    contained the destination of a redirect
+    CVE-2021-23973: MediaError message property could have leaked information
+                    about cross-origin resources
+    CVE-2021-23978: Memory safety bugs fixed in Thunderbird 78.8
+
+ -- Carsten Schoenert <c.schoenert@t-online.de>  Sun, 21 Feb 2021 14:58:05 +0100
+
 thunderbird (1:78.7.1-1) unstable; urgency=medium
 
   * [406f9d7] New upstream version 78.7.1