chore(helm): update skip-db-update environment variable

[mmorejon]

Description

Use TRIVY_SKIP_DB_UPDATE instead of TRIVY_SKIP_UPDATE.

Related issues

• Close chore(helm): use TRIVY_SKIP_DB_UPDATE instead of TRIVY_SKIP_UPDATE #3656

Before

2023-02-20T16:59:57.928Z        WARN    'TRIVY_SKIP_UPDATE' is deprecated. Use 'TRIVY_SKIP_DB_UPDATE' instead.
2023-02-20T16:59:57.931Z        INFO    Listening 0.0.0.0:4954...

After

2023-02-20T16:59:57.931Z        INFO    Listening 0.0.0.0:4954...

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[CLAassistant]

All committers have signed the CLA.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[knqyf263]

Thanks