Mark Tails 4.10 as released.

debian/changelog

-tails (4.10) UNRELEASED; urgency=medium
+tails (4.10) unstable; urgency=medium
 
   * Security fixes
     - Upgrade Tor Browser to 9.5.4-build1 (Closes: #17885).
@@ -55,7 +55,7 @@ tails (4.10) UNRELEASED; urgency=medium
     - Update expected title of the GitLab page we use
     - Rubocop: target Ruby 2.5 (Buster).
 
- -- Tails developers <tails@boum.org>  Sun, 23 Aug 2020 14:16:14 +0200
+ -- Tails developers <tails@boum.org>  Mon, 24 Aug 2020 13:28:43 +0200
 
 tails (4.9) unstable; urgency=medium