Add helm shield (apache#10526)

README.md

@@ -22,6 +22,7 @@
 [![Language grade: Java](https://img.shields.io/lgtm/grade/java/g/apache/druid.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/apache/druid/context:java)
 [![Coverage Status](https://img.shields.io/codecov/c/gh/apache/druid)](https://codecov.io/gh/apache/druid)
 [![Docker](https://img.shields.io/badge/container-docker-blue.svg)](https://hub.docker.com/r/apache/druid)
+[![Helm](https://img.shields.io/badge/helm-druid-5F90AB?logo=helm)](https://artifacthub.io/packages/helm/helm-incubator/druid)
 <!--- Following badges are disabled until they can be fixed: -->
 <!--- [![Inspections Status](https://img.shields.io/teamcity/http/teamcity.jetbrains.com/s/OpenSourceProjects_Druid_Inspections.svg?label=TeamCity%20inspections)](https://teamcity.jetbrains.com/viewType.html?buildTypeId=OpenSourceProjects_Druid_Inspections) -->