docs: update the code-of-conduct to follow the CNCF

[chlins]

This pull request updates the project's code of conduct to align with the CNCF Code of Conduct, replacing the previous Contributor Covenant Code of Conduct with a concise reference to the CNCF guidelines.

Code of Conduct Update:

• CODE_OF_CONDUCT.md: Replaced the detailed Contributor Covenant Code of Conduct with a reference to the CNCF Code of Conduct. This change simplifies the document while ensuring alignment with the CNCF community standards.

Description

Related Issue

Motivation and Context

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation Update (if none of the other choices apply)

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.