fix: sign charts with digest

.github/actions/pr-chart/action.yaml

@@ -103,10 +103,26 @@ runs:
         helm package ${{ inputs.chart }} --version ${{ env.PR_COMMIT_TAG }}
         helm push ${{ inputs.registry-repo }}-${{ env.PR_COMMIT_TAG }}.tgz oci://${{ env.CHART_PROJECT }}
 
+    - name: get digest
+      id: digest
+      if: steps.helm.outcome == 'success'
+      shell: bash
+      run: |
+        helm show chart ${{ inputs.registry-repo }}-${{ env.PR_COMMIT_TAG }}
+        curl -s -u ${{ inputs.registry-user }}:${{ inputs.registry-token }} "https://${{ inputs.registry }}/service/token?service=service=harbor-registry&scope=repository:${{ inputs.registry-repo }}:pull"
+
+        curl -s -H "Authorization: Bearer $TOKEN" "Accept: application/vnd.oci.image.manifest.v1+json" https://${{ inputs.registry }}/${{ env.CHART_PROJECT }}/manifests/${{ env.PR_TAG }}
+        digest=$(curl -s -H "Accept: application/vnd.oci.image.manifest.v1+json" https://${{ inputs.registry }}/${{ inputs.registry-repo }}/manifests/${{ env.PR_TAG }} | jq -r '.config.digest')
+        echo ${digest}
+        echo "digest=${digest}" >> "$GITHUB_OUTPUT"
+
+
+
     - name: build success
       if: steps.helm.outcome == 'success'
       shell: bash
       run: |
+        echo "${{steps.digest.outputs.digest}}"
         echo "${SUMMARY}" >> "$GITHUB_STEP_SUMMARY"
       env:
         SUMMARY: |