Update CHANGELOG with information about optimize-use command.

Author: beberlei

CHANGELOG.md

@@ -4,3 +4,8 @@
   various fixes that are aggreated under the GH-28, GH-29, GH-19
   and GH-20. The command is now much more robust and does
   not create false/positives anymore.
+
+- Added `optimize-use <file>` command that will convert all
+  relative or absolute usages of namespaces into use statements,
+  leaving only the last part at the occuring position.
+  (by @pscheit)