Add feedback request to README (#2438)

README.rst

@@ -92,6 +92,20 @@ Documentation for the client is `available on elastic.co`_ and `Read the Docs`_.
 .. _Read the Docs: https://elasticsearch-py.readthedocs.io
 
 
+Feedback 🗣️
+-----------
+
+The engineering team here at Elastic is looking for developers to participate in
+research and feedback sessions to learn more about how you use our Python client and
+what improvements we can make to their design and your workflow. If you're interested in
+sharing your insights into developer experience and language client design, please fill
+out this `short form`_. Depending on the number of responses we get, we may either
+contact you for a 1:1 conversation or a focus group with other developers who use the
+same client. Thank you in advance - your feedback is crucial to improving the user
+experience for all Elasticsearch developers!
+
+.. _short form: https://forms.gle/bYZwDQXijfhfwshn9
+
 License
 -------