Fix failing image-builder targets

[richardcase]

/kind bug

What steps did you take and what happened:

When building AMIs for CAPA there are a number of targets OS's that are failing to build. We need to investigate and decide if we want to fix / support these:

• amazon-2 (error: Failure downloading https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm)
• centos-7 (error: Failure downloading https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm)
• rockylinux-8 (error: amazon-ebs.rockylinux-8: No AMI was found matching filters)

What did you expect to happen:

I expect any supported OS by CAPA to have the AMIs building successfully.

Anything else you would like to add: [Miscellaneous information that will assist in solving the issue.]

Environment:

• Cluster-api-provider-aws version:
• Kubernetes version: (use kubectl version):
• OS (e.g. from /etc/os-release):

[richardcase]

/help /triage accepted /priority important-soon

[k8s-ci-robot]

@richardcase: This request has been marked as needing help from a contributor.

Guidelines

Please ensure that the issue body includes answers to the following questions:

• Why are we solving this issue?
• To address this issue, are there any code changes? If there are code changes, what needs to be done in the code and what places can the assignee treat as reference points?
• Does this issue have zero to low barrier of entry?
• How can the assignee reach out to you for help?

For more details on the requirements of such an issue, please see here and ensure that they are met.

If this request no longer meets these requirements, the label can be removed by commenting with the /remove-help command.

In response to [this](https://github.com/kubernetes-sigs/cluster-api-provider-aws/issues/5142): >/help >/triage accepted >/priority important-soon Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.