Add changelog entry.

debian/changelog

@@ -1,3 +1,12 @@
+livecd-rootfs (2.770) UNRELEASED; urgency=medium
+
+  [ Alexandre Ghiti ]
+  * Fix SiFive Unmatched build. While merging the VisionFive support, we
+    removed the installation of u-boot-menu for the Unmatched by mistake
+    (LP: #1982735).
+
+ -- Łukasz 'sil2100' Zemczak <lukasz.zemczak@ubuntu.com>  Mon, 25 Jul 2022 10:18:50 +0200
+
 livecd-rootfs (2.769) kinetic; urgency=medium
 
   [ Alexandre Ghiti ]