fix: extract chart digest from helm push output

The oras resolve command fails with 'not found' immediately after helm push.
Instead, extract the digest directly from helm push output which already
contains the digest information (format: 'Digest: sha256:...').

On-behalf-of: Gerald Morrison (SAP) <gerald.morrison@sap.com>
Signed-off-by: Gerald Morrison (SAP) <gerald.morrison@sap.com>

Author: morrison-sap

.github/workflows/kubernetes-controller-new.yml

@@ -360,27 +360,28 @@ jobs:
         run: oras tag "${IMAGE_NAME}:${VERSION}" latest
 
       - name: Package and push Helm chart
+        id: chart-push
         working-directory: ${{ env.LOCATION }}
         env:
           VERSION: ${{ needs.build.outputs.version }}
           IMAGE_DIGEST: ${{ steps.image-digest.outputs.digest }}
         run: |
           task helm/package VERSION="${VERSION}" APP_VERSION="${VERSION}" IMAGE_DIGEST="${IMAGE_DIGEST}"
-          helm push dist/ocm-k8s-toolkit-${VERSION}.tgz oci://${{ env.REGISTRY }}/${{ github.repository_owner }}/kubernetes/controller/chart
-
-      - name: Resolve chart digest
-        id: chart-digest
-        env:
-          VERSION: ${{ needs.build.outputs.version }}
-        run: |
-          CHART_REPO="${{ env.REGISTRY }}/${{ github.repository_owner }}/kubernetes/controller/chart"
-          echo "digest=$(oras resolve ${CHART_REPO}:${VERSION})" >> "$GITHUB_OUTPUT"
+          
+          # Push chart and capture digest from output
+          PUSH_OUTPUT=$(helm push dist/ocm-k8s-toolkit-${VERSION}.tgz oci://${{ env.REGISTRY }}/${{ github.repository_owner }}/kubernetes/controller/chart 2>&1)
+          echo "$PUSH_OUTPUT"
+          
+          # Extract digest from helm push output (format: "Digest: sha256:...")
+          CHART_DIGEST=$(echo "$PUSH_OUTPUT" | grep -oP 'Digest: \Ksha256:[a-f0-9]+')
+          echo "digest=${CHART_DIGEST}" >> "$GITHUB_OUTPUT"
+          echo "✓ Chart pushed with digest: ${CHART_DIGEST}"
 
       - name: Attest chart
         uses: actions/attest-build-provenance@977bb373ede98d70efdf65b84cb5f73e068dcc2a # v3
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
-          subject-digest: ${{ steps.chart-digest.outputs.digest }}
+          subject-digest: ${{ steps.chart-push.outputs.digest }}
           subject-name: ${{ env.REGISTRY }}/${{ github.repository_owner }}/kubernetes/controller/chart
           push-to-registry: true