Mark Tails 4.5~rc1 as released.

debian/changelog

-tails (4.5~rc1) UNRELEASED; urgency=medium
+tails (4.5~rc1) unstable; urgency=medium
 
   * Major changes
     - Migrate from aufs to overlayfs (Closes: #8415). This change touches
@@ -66,7 +66,7 @@ tails (4.5~rc1) UNRELEASED; urgency=medium
     - Make chutney log what it is doing.
     - Make opening Thunderbird's Extensions tab more robust.
 
- -- Tails developers <tails@boum.org>  Thu, 26 Mar 2020 01:56:35 +0100
+ -- Tails developers <tails@boum.org>  Thu, 26 Mar 2020 22:51:35 +0100
 
 tails (4.4.1) unstable; urgency=medium