ci: parallelize building images for different archs

As it appears, there are some SSL/TLS issues appearing in the container
image builds for the `ppc64le` architecture which, in the end, results
in build and push failure for all architecture, therefore parallelize
those image builds (even if it costs GitHub some resources) to avoid
failing altogether.

Signed-off-by: Matej Focko <[email protected]>

.github/workflows/base-image-rebuild.yml

@@ -22,6 +22,13 @@ jobs:
         include:
           - containerfile: containers/Containerfile
             tags: "fedora latest"
+            archs: "amd64"
+          - containerfile: containers/Containerfile
+            tags: "fedora latest"
+            archs: "arm64"
+          - containerfile: containers/Containerfile
+            tags: "fedora latest"
+            archs: "ppc64le"
 
     steps:
       - uses: actions/checkout@v3
@@ -38,7 +45,7 @@ jobs:
           containerfiles: ${{ matrix.containerfile }}
           image: base
           tags: ${{ matrix.tags }}
-          archs: amd64, arm64, ppc64le
+          archs: ${{ matrix.archs }}
           # Uncomment once we stop using oc cluster up for tests
           #           oci: true