Prepare 2.5.1

Signed-off-by: Rudi Grinberg <me@rgrinberg.com>

CHANGES.md

@@ -1,13 +1,13 @@
-2.5.1 (unreleased)
+2.5.1 (17/04/2020)
 ------------------
 
 - [coq] Fix install .v files for Coq theories (#3384, @lthms)
 
-- [coq] Fix install path for theory names with level greater than 1
-  (#3358 , @ejgallego)
+- [coq] Fix install path for theory names with level greater than 1 (#3358,
+  @ejgallego)
 
-- Fix a bug introduced in 2.0.0 where the [locks] field in rules with no targets had
-  no effect. (@aalekseyev, report by @craigfe)
+- Fix a bug introduced in 2.0.0 where the [locks] field in rules with no targets
+  had no effect. (@aalekseyev, report by @craigfe)
 
 2.5.0 (09/04/2020)
 ------------------