Add notice for chunk storage removal (#4743)

Signed-off-by: Alvin Lin <[email protected]>

Author: alvinlin123

README.md

@@ -19,6 +19,13 @@ Prometheus sources in a single cluster, allowing untrusted parties to share the
 Cortex is a [CNCF](https://cncf.io) incubation project used in several production systems including [Weave Cloud](https://cloud.weave.works) and [Grafana Cloud](https://grafana.com/cloud).
 Cortex is primarily used as a [remote write](https://prometheus.io/docs/operating/configuration/#remote_write) destination for Prometheus, with a Prometheus-compatible query API.
 
+
+## Chunk Storage Deprecation Notice
+
+The chunks storage is deprecated since v1.10.0. You're encouraged to use the [blocks storage](docs/blocks-storage/_index.md).
+
+Chunks storage is scheduled to be removed in release 1.14.0
+
 ## Documentation
 
 Read the [getting started guide](https://cortexmetrics.io/docs/getting-started) if you're new to the

docs/chunks-storage/_index.md

@@ -1,11 +1,18 @@
 ---
-title: "Chunks Storage (deprecated)"
-linkTitle: "Chunks Storage (deprecated)"
+title: "Chunks Storage (deprecated and pending removal)"
+linkTitle: "Chunks Storage (deprecated and pending removal)"
 weight: 4
 menu:
 ---
 
-**Warning: the chunks storage is deprecated. You're encouraged to use the [blocks storage](../blocks-storage/_index.md).**
+## Deprecation Notice
+
+The chunks storage is deprecated since v1.10.0. You're encouraged to use the [blocks storage](../blocks-storage/_index.md).
+
+Chunks storage is scheduled to be removed in release 1.14.0
+
+
+## Introduction
 
 The chunks storage is a Cortex storage engine which stores each single time series into a separate object called _chunk_. Each chunk contains the samples for a given period (defaults to 12 hours). Chunks are then indexed by time range and labels, in order to provide a fast lookup across many (over millions) chunks. For this reason, the Cortex chunks storage requires two backend storages: a key-value store for the index and an object store for the chunks.