update(build/registry): allow optional auth to update-index cmd

[brennoo]

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind feature

/kind bug

/kind cleanup

/kind design

/kind documentation

/kind failing-test

Any specific area of the project related to this PR?

Uncomment one (or more) /area <> lines:

/area rules

/area registry

/area build

/area documentation

Proposed rule maturity level

Uncomment one (or more) /area <> lines (only for PRs that add or modify rules):

/area maturity-stable

/area maturity-incubating

/area maturity-sandbox

/area maturity-deprecated

What this PR does / why we need it:

Hi team, this PR allows to authenticate to the registry during update-index if the credentials are set

Which issue(s) this PR fixes:
This is not an issue for the public repository but we are relying on the registry tool to build/push our private repo indexes and it needs authentication.

Fixes #

Special notes for your reviewer:

[LucaGuerra]

Thank you for this PR! The env variables are consistent with the push command so we can definitely merge this. However, while you absolutely can use our code in your workflow, please note that the build tool is technically part of the rules CI/CD process and it is not a tool that we are looking to support for general use, this means that we may break those interfaces or change the meaning of the commands without release notes or breaking change notices;

For general use cases I would recommend looking into the falcoctl command line tool if that fits the use you have in mind. If not, feedback (and contributions!) are appreciated to make it easier to use for CI/CD processes.

Again, thanks for the contribution! 🚀

[poiana]

LGTM label has been added.

Git tree hash: f2d66e6844f07d0c34504b860ad65e0a6d6de223

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: brennoo, LucaGuerra

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