Fix failing image-builder targets

/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):