Build under MacOS.

[michaelfig]

Signed-off-by: Michael FIG michael@liveblockauctions.com

What this PR does / why we need it:

Updates the build instructions and Makefile rule to allow cross-platform builds of Docker images from a MacOS host. It probably works for Windows, too, but it is not tested.

Which issue this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close that issue when PR gets merged): n/a

Special notes for your reviewer:

The --platforms flag enables Bazel rules for the Go Linux cross-compiler.

Release note:

Update build instructions and enable building under MacOS.

[jetstack-bot]

Hi @michaelfig. Thanks for your PR.

I'm waiting for a jetstack or cert-manager member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[munnerz]

/ok-to-test

[munnerz]

Thanks for this! 😄

/lgtm
/approve

[jetstack-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: michaelfig, munnerz

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