Only build nginx-errors for linux/amd64

[DysphoricUnicorn]

What this PR does / why we need it:

This PR changes the Makefile for the nginx-errors example to only build amd64 images.
This is done because the build is currently failing due to multiarch builds taking too many resources.

I also updated the container image link in the docs because I had accidentally used an incorrect one in my previous PR (#7460)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  -> kind of, considering non-amd64 images will no longer be built automatically

How Has This Been Tested?

I built the images using the updated Makefile on my local Linux machine and it worked as expected.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I've read the CONTRIBUTION guide
• I have added tests to cover my changes. -> does not apply
• All new and existing tests passed. -> does not apply

[k8s-ci-robot]

@DysphoricUnicorn: This issue is currently awaiting triage.

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[k8s-ci-robot]

Hi @DysphoricUnicorn. Thanks for your PR.

I'm waiting for a kubernetes 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.

I understand the commands that are listed here.

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.

[rikatz]

/ok-to-test

[rikatz]

/lgtm
/approve
Thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: DysphoricUnicorn, rikatz

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• OWNERS [rikatz]

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