chore: remove rhel from image build workflow

This removes rhel-8 from the image builder workflow as there are
issues with the target currently with target in image-builder for
AMIs.

Signed-off-by: Richard Case <[email protected]>

Author: richardcase

.github/workflows/build-ami.yml

@@ -37,7 +37,7 @@ jobs:
   buildandpublish:
     strategy:
       matrix:
-        target: ['ubuntu-2204', 'ubuntu-2404', 'flatcar', 'rhel-8']
+        target: ['ubuntu-2204', 'ubuntu-2404', 'flatcar']
       max-parallel: 1
       fail-fast: false
     name: Build and publish CAPA AMIs