Mark Tails 4.8 as released.

debian/changelog

-tails (4.8) UNRELEASED; urgency=medium
+tails (4.8) unstable; urgency=medium
 
   * Major changes
     - Welcome Screen: after a large refactoring we now can persist
@@ -76,7 +76,7 @@ tails (4.8) UNRELEASED; urgency=medium
     - Verify that the Unsafe Browser is disabled by default.
     - Test suite: fix --image-bumping-mode.
 
- -- Tails developers <tails@boum.org>  Mon, 29 Jun 2020 10:11:36 +0200
+ -- Tails developers <tails@boum.org>  Mon, 29 Jun 2020 16:02:18 +0200
 
 tails (4.7) unstable; urgency=medium