🤖 Sync code of conduct from upstream repo (#1997)

Use exercism.org instead of exercism.io
exercism/org-wide-files#180

Author: exercism-bot

CODE_OF_CONDUCT.md

@@ -6,7 +6,7 @@ Exercism is a platform centered around empathetic conversation. We have a low to
 
 ## Seen or experienced something uncomfortable?
 
-If you see or experience abuse, harassment, discrimination, or feel unsafe or upset, please email abuse@exercism.io. We will take your report seriously.
+If you see or experience abuse, harassment, discrimination, or feel unsafe or upset, please email abuse@exercism.org. We will take your report seriously.
 
 ## Enforcement