DOC: Updated the CHANGELOG

Author: ArthurJWH

CHANGELOG.md

@@ -39,6 +39,7 @@ Attention: The newest changes should be on top -->
 - ENH: Discretized and No-Pickle Encoding Options [#827](https://github.com/RocketPy-Team/RocketPy/pull/827)
 - ENH: Add the Coriolis Force to the Flight class [#799](https://github.com/RocketPy-Team/RocketPy/pull/799)
 - ENH: Improve parachute geometric parametrization [#835](https://github.com/RocketPy-Team/RocketPy/pull/835)
+- ENH: Changing ellipses plot axis label [#855](https://github.com/RocketPy-Team/RocketPy/pull/855)
 
 ### Changed