docs: Remove CODE_OF_CONDUCT, add Contributing

Author: toshimaru

CODE_OF_CONDUCT.md

@@ -11,6 +11,7 @@
 # Gemfile
 gem "serverkit-vscode"
 ```
+
 ## Resource
 
 ### vscode_package
@@ -33,10 +34,10 @@ resources:
     version: 1.156.0
 ```
 
-## License
+## Contributing
 
-The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).
+Bug reports and pull requests are welcome on GitHub at [serverkit/serverkit-vscode](https://github.com/serverkit/serverkit-vscode).
 
-## Code of Conduct
+## License
 
-Everyone interacting in the Serverkit::Vscode project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/toshimaru/serverkit-vscode/blob/master/CODE_OF_CONDUCT.md).
+The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).