Update release notes

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

RELEASE_NOTES.md

@@ -12,7 +12,8 @@
 
 * Extra validation check to ensure the quantity is strictly positive.
 * Extra validation check to ensure the quantity and price are within the allowed bounds.
-* Add more edge cases to the integration tests
+* Add more edge cases to the integration tests.
+* Add idiomatic string representations for `Power` and `Price` classes.
 
 ## Bug Fixes