Update CODE_OF_CONDUCT.md
correct URL markdown formating
# Contributor Code of Conduct
-Please refer to the contributor Code of Conduct at the Home repository [here](https://github.com/nanoframework/Home/blob/master/CODE_OF_CONDUCT.md.
+Please refer to the contributor Code of Conduct at the Home repository [here](https://github.com/nanoframework/Home/blob/master/CODE_OF_CONDUCT.md).
