fix coc urls

Author: sckott

CODE_OF_CONDUCT.md

@@ -21,5 +21,5 @@ Instances of abusive, harassing, or otherwise unacceptable behavior may be repor
 opening an issue or contacting one or more of the project maintainers.
 
 This Code of Conduct is adapted from the Contributor Covenant 
-(http:contributor-covenant.org), version 1.0.0, available at 
-http://contributor-covenant.org/version/1/0/0/
+(https://contributor-covenant.org), version 1.0.0, available at 
+https://contributor-covenant.org/version/1/0/0/