Remove trailing whitespace from changelog

Author: NathanReb

CHANGES.md

@@ -11,7 +11,7 @@
 
 ### Changed
 
-- Command `tag`: improve error and log messages by comparing the provided 
+- Command `tag`: improve error and log messages by comparing the provided
   commit with the commit correspondent to the provided tag (#226, @pitag-ha)
 - Error logs: when an external command fails, include its error message in
   the error message posted by `dune-release` (#231, @pitag-ha)