fix: trivy db repository credential set

[kimtaehong]

Description

Regarding the issue in #2063, I checked the code and realized that environment value (TRIVY_USER/TRIVY_PASSWORD) is not set at initContainer step.

So I looked at the related code, and it seemed to be caused by the DB Registry User/Password information set in k8s secret being set to refer to ConfigMap data.

func (c Config) TrivyDBRepositoryCredentialsSet() bool {
	_, userOk := c.Data[keyTrivyDBRepositoryUsername]
	_, passOk := c.Data[keyTrivyDBRepositoryPassword]
	return userOk && passOk
}

I tried putting the trivy db private registry credentials in the configmap and it worked fine, but I think it should be referencing secret as originally intended, please confirm

Related issues

• Close private db registry authentication error #2063

Checklist

• I've read the guidelines for contributing to this repository.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[chen-keinan]

@kimtaehong lgtm 🚀 thanks for the contributions