Description of problem:

The documentation for 1.20 has several gaps regarding Tekton Results' retention agent configuration:

• The new field defaultRetention is not mentioned in the RN except under the Deprecations section. While maxRetention was deprecated in favor of defaultRetention, the new config field should be included in its own bullet point.
• The new retention config option policy is not mentioned in the release notes or documentation
• The Tekton Results configuration docs do not mention the config options defaultRetention or policy , and only documents the deprecated option maxRetention