Fix helm not found in CI pipeline (#8281)

Author: AlexFenlon

.github/workflows/publish-helm.yml

@@ -84,6 +84,11 @@ jobs:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
 
+      - name: Setup Helm
+        uses: azure/setup-helm@1a275c3b69536ee54be43f2070a358922e12c8d4 # v4.3.1
+        with:
+          version: 'v3.18.6'
+
       - name: Package
         id: package
         run: |