Update CONTRIBUTING.md

Author: Edrig

CONTRIBUTING.md

@@ -6,7 +6,7 @@ SPDX-License-Identifier: MIT
 
 # Contributing
 Please note that this project is released with a
-[Contributor Code of Conduct](https://github.com/adafruit/circuitpython/blob/main/CODE_OF_CONDUCT.md).
+[Contributor Code of Conduct](CODE_OF_CONDUCT.md).
 By participating in this project you agree to abide by its terms. Participation
 covers any forum used to converse about CircuitPython including unofficial and official spaces. Failure to do
 so will result in corrective actions such as time out or ban from the project.