katapult: Add a Config_changes.md entry for flashtool.py renaming

Signed-off-by: Robert Schiele <rschiele@gmail.com>

Author: schiele

docs/Config_Changes.md

@@ -8,6 +8,13 @@ All dates in this document are approximate.
 
 ## Changes
 
+20260408: The script `lib/canboot/flash_can.py` has been updated to
+the most current version from
+[Katapult](https://github.com/Arksine/katapult) and as such renamed to
+`lib/katapult/flashtool.py`.  If you call this script directly instead
+of using the existing Makefiles, you will need to change the path to
+the script to `lib/katapult/flashtool.py`.
+
 20260318: The `[probe_eddy_current]` config options `speed`,
 `lift_speed`, `samples`, `sample_retract_dist`, `samples_result`,
 `samples_tolerance`, and `samples_tolerance_retries` no longer apply