Add ArtifactHub badge

Signed-off-by: Kai Tillman <ktillman@datawire.io>

README.md

@@ -6,6 +6,7 @@ Emissary-ingress
 [![Docker Repository][badge-docker-img]][badge-docker-link]
 [![Join Slack][badge-slack-img]][badge-slack-link]
 [![Core Infrastructure Initiative: Best Practices][badge-cii-img]][badge-cii-link]
+[![Artifact HUB][badge-artifacthub-img]][badge-artifacthub-link]
 
 [badge-version-img]: https://img.shields.io/docker/v/emissaryingress/emissary?sort=semver
 [badge-version-link]: https://github.com/emissary-ingress/emissary/releases
@@ -15,6 +16,8 @@ Emissary-ingress
 [badge-slack-link]: https://communityinviter.com/apps/cloud-native/cncf
 [badge-cii-img]: https://bestpractices.coreinfrastructure.org/projects/1852/badge
 [badge-cii-link]: https://bestpractices.coreinfrastructure.org/projects/1852
+[badge-artifacthub-img]: https://img.shields.io/endpoint?url=https://artifacthub.io/badge/repository/emissary-ingress
+[badge-artifacthub-link]: https://artifacthub.io/packages/helm/datawire/emissary-ingress
 
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