Added upgrading.md file and updated it for opensearch-py 2.2.0 release (

opensearch-project#293)

Signed-off-by: saimedhi <saimedhi@amazon.com>

CHANGELOG.md

@@ -3,9 +3,12 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [2.1.1]
 ### Added
+- Merging opensearch-dsl-py into opensearch-py ([#287](https://github.com/opensearch-project/opensearch-py/pull/287))
+- Added upgrading.md file and updated it for opensearch-py 2.2.0 release ([#293](https://github.com/opensearch-project/opensearch-py/pull/293))
 ### Changed
 ### Deprecated
 ### Removed
+- Removed 'out/opensearchpy' folder which was produced while generating pyi files for plugins ([#288](https://github.com/opensearch-project/opensearch-py/pull/288))
 ### Fixed
 - Fixed SigV4 Signing for Managed Service ([#279](https://github.com/opensearch-project/opensearch-py/pull/279))
 - Fixed SigV4 Signing for Async Requests with QueryStrings ([#272](https://github.com/opensearch-project/opensearch-py/pull/279))
@@ -32,7 +35,6 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added SigV4 support for Async Opensearch Client ([#254](https://github.com/opensearch-project/opensearch-py/pull/254))
 - Compatibility with OpenSearch 2.1.0 - 2.4.1 ([#257](https://github.com/opensearch-project/opensearch-py/pull/257))
 - Adding explicit parameters for AIOHttpConnection and AsyncTransport ([#276](https://github.com/opensearch-project/opensearch-py/pull/276))
-- Merging opensearch-dsl-py into opensearch-py ([#287](https://github.com/opensearch-project/opensearch-py/pull/287))
 ### Changed
 - Updated getting started to user guide ([#233](https://github.com/opensearch-project/opensearch-py/pull/233))
 - Updated CA certificate handling to check OpenSSL environment variables before defaulting to certifi ([#196](https://github.com/opensearch-project/opensearch-py/pull/196))
@@ -43,7 +45,6 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### Removed
 - Removed patch versions in integration tests for OpenSearch 1.0.0 - 2.3.0 to reduce Github Action jobs ([#262](https://github.com/opensearch-project/opensearch-py/pull/262))
-- Removed 'out/opensearchpy' folder which was produced while generating pyi files for plugins ([#288](https://github.com/opensearch-project/opensearch-py/pull/288))
 ### Fixed
 - Fixed DeprecationWarning emitted from urllib3 1.26.13+ ([#246](https://github.com/opensearch-project/opensearch-py/pull/246))
 ### Security

UPGRADING.md

@@ -0,0 +1,24 @@
+- [Upgrading OpenSearch Python Client](#upgrading-opensearch-python-client)
+  - [Upgrading to >= 2.2.0](#upgrading-to->=-2.2.0)
+    - [Features from High-Level Python Client](#features-from-high-level-python-client)
+    - [API Implementation differences for existing opensearch-dsl-py users](#api-implementation-differences-for-existing-opensearch-dsl-py-users)
+
+
+# Upgrading OpenSearch Python Client
+
+## Upgrading to >= 2.2.0
+
+opensearch-py now includes [opensearch-dsl-py](https://pypi.org/project/opensearch-dsl/) features. opensearch-dsl-py was merged into opensearch-py preserving backwards compatibility with the previous opensearch-py version. (Refer [link](https://github.com/opensearch-project/opensearch-py/pull/287))
+
+
+### Features from High-Level Python Client
+
+opensearch-py functionalities that already exist are not altered. 
+
+The opensearchpy [helpers](https://github.com/opensearch-project/opensearch-py/tree/main/opensearchpy/helpers) module now provides access to aggs, analysis, document, faceted search, field, function, index, mapping, query, search, update by query, utils, and wrappers. As a result, without importing opensearch-dsl-py, these functionalities can be imported directly from opensearch-py. 
+
+
+### API Implementation differences for existing opensearch-dsl-py users 
+
+The functionalities from opensearch-dsl-py are merged into this client. Refer to the [USER_GUIDE](https://github.com/opensearch-project/opensearch-py/blob/main/USER_GUIDE.md#using-high-level-python-client) for an example on how to implement a feature from the previously known high level Python client.
+