CONTRIBUTING.md: use proper 'Code of Conduct' file

Signed-off-by: Maxim Belkin <[email protected]>

Author: maxim-belkin

CONTRIBUTING.md

@@ -15,7 +15,7 @@ In exchange,
 we will address your issues and/or assess your change proposal as promptly as we can,
 and help you become a member of our community.
 Everyone involved in [Software Carpentry][swc-site] and [Data Carpentry][dc-site]
-agrees to abide by our [code of conduct](CONDUCT.md).
+agrees to abide by our [code of conduct](CODE_OF_CONDUCT.md).
 
 ## How to Contribute