Set release in changelog

CHANGELOG

@@ -1,5 +1,5 @@
-Release 6.0.7 (Not yet released)
--------------------------------
+Release 6.0.7
+-------------
  * Addresses regression introduced in 6.0.5 when attempting to establish database connection after fork and activerecord is not configured in the expected way. Closes GH-2281.
  * Addresses regression introduced in 5.1.5 where hook scripts would fail to run. As a result the PASSENGER_ERROR_PAGE and PASSENGER_CONFIG_MANIFEST env vars have been removed from the passenger hook script environment.
  * Match static rails assets on 8-digit content hash. Contributed by @mattozinga.
@@ -25,7 +25,7 @@ Release 6.0.7 (Not yet released)
     - OpenSSL 1.1.1h (was 1.0.2u)
 
 Release 6.0.6
--------------------------------
+-------------
  * Update gemspec with up to date metadata.
  * Reverts the addition of the 'etc' gem to the Passenger gemspec, because it broke on normal ruby installs. Closes GH-2283.
  * Builds Ubuntu focal Nginx dynamic module package against Nginx 1.18.0. Closes GH-2291.