fix: use errors pkg for comparison

[PascalBourdier]

follow this best practice: https://go.dev/wiki/ErrorValueFAQ#how-should-i-change-my-error-handling-code-to-work-with-the-new-features

Related Issue or Design Document

Checklist

• I have read the contributing guidelines and signed the CLA.
• I have referenced an issue containing the design document if my change introduces a new feature.
• I have read the security policy.
• I confirm that this pull request does not address a security vulnerability.
  If this pull request addresses a security vulnerability,
  I confirm that I got approval (please contact [email protected]) from the maintainers to push the changes.
• I have added tests that prove my fix is effective or that my feature works.
• I have added the necessary documentation within the code base (if appropriate).

Further comments

[CLAassistant]

All committers have signed the CLA.

[alnr]

Thank you! One oversight I noticed.

[alnr]

Thanks!

CI is borked once again, don't know whats up there.

[alnr]

Please rebase onto master once #621 is merged (fixes CI).