Allow multiplatform build to pull image with arch manifest

[troy0820]

What does this change

Without this, trying to run a demo the image fails because it doesn't have the GOOS/GOARCH in the manifest with k8s.

What issue does it fix

Didn't create one

Notes for the reviewer

Checklist

• [ ] Did you write tests?
• [ ] Did you write documentation?
• [ ] Did you make any API changes? Update the corresponding API documentation.

[codecov[bot]]

Codecov Report

Merging #279 (882c56f) into main (f8cf3f6) will not change coverage. Report is 1 commits behind head on main. The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #279   +/-   ##
=======================================
  Coverage   68.85%   68.85%           
=======================================
  Files          14       14           
  Lines        2244     2244           
=======================================
  Hits         1545     1545           
  Misses        548      548           
  Partials      151      151           

Flag	Coverage Δ
unittests	68.85% <ø> (ø)

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[troy0820]

docker manifest inspect ghcr.io/getporer/porter-operator:v1.0.0

{
   "schemaVersion": 2,
   "mediaType": "application/vnd.oci.image.index.v1+json",
   "manifests": [
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 2372,
         "digest": "sha256:c05bc591cd0288a9805ebd9f89520013243775a5d9fa691a017dd218ba00fb77",
         "platform": {
            "architecture": "arm64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 2372,
         "digest": "sha256:cc3c904b67da278128481304169268c15a075c83df467adcfdadf64f39e93490",
         "platform": {
            "architecture": "amd64",
            "os": "linux"
         }
      },
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 566,
         "digest": "sha256:6ff4de306a9101d610f67531191ca32a81021ee114c99ebf39bae6eb0d60dca6",
         "platform": {
            "architecture": "unknown",
            "os": "unknown"
         }
      },
      {
         "mediaType": "application/vnd.oci.image.manifest.v1+json",
         "size": 566,
         "digest": "sha256:79915147b7f5e4daec3546127aaf0d488cb375a1f0fb8ac69f78c11af94898c3",
         "platform": {
            "architecture": "unknown",
            "os": "unknown"
         }
      }
   ]
}