[incubator/schema-registry] add repo archive notice (#24064)

Signed-off-by: Scott Rigby <scott@r6by.com>

incubator/schema-registry/Chart.yaml

@@ -1,6 +1,6 @@
 name: schema-registry
 home: https://docs.confluent.io/current/schema-registry/docs/index.html
-version: 1.2.1
+version: 1.2.2
 appVersion: 5.0.1
 keywords:
   - confluent

incubator/schema-registry/README.md

@@ -1,3 +1,8 @@
+# ⚠️ Repo Archive Notice
+
+As of Nov 13, 2020, charts in this repo will no longer be updated.
+For more information, see the Helm Charts [Deprecation and Archive Notice](https://github.com/helm/charts#%EF%B8%8F-deprecation-and-archive-notice), and [Update](https://helm.sh/blog/charts-repo-deprecation/).
+
 # Schema-Registry Helm Chart
 This helm chart creates a [Confluent Schema-Registry server](https://github.com/confluentinc/schema-registry).