Upgrade chat links and badges to Matrix (#7345)

(cherry picked from commit fb7a0a1)

README.rst

@@ -25,9 +25,13 @@ Async http client/server framework
    :target: https://docs.aiohttp.org/
    :alt: Latest Read The Docs
 
-.. image:: https://badges.gitter.im/Join%20Chat.svg
-   :target: https://gitter.im/aio-libs/Lobby
-   :alt: Chat on Gitter
+.. image:: https://img.shields.io/matrix/aio-libs:matrix.org?label=Discuss%20on%20Matrix%20at%20%23aio-libs%3Amatrix.org&logo=matrix&server_fqdn=matrix.org&style=flat
+   :target: https://matrix.to/#/%23aio-libs:matrix.org
+   :alt: Matrix Room — #aio-libs:matrix.org
+
+.. image:: https://img.shields.io/matrix/aio-libs-space:matrix.org?label=Discuss%20on%20Matrix%20at%20%23aio-libs-space%3Amatrix.org&logo=matrix&server_fqdn=matrix.org&style=flat
+   :target: https://matrix.to/#/%23aio-libs-space:matrix.org
+   :alt: Matrix Space — #aio-libs-space:matrix.org
 
 
 Key Features

setup.cfg

@@ -3,7 +3,8 @@ name = aiohttp
 version = attr: aiohttp.__version__
 url = https://github.com/aio-libs/aiohttp
 project_urls =
-  Chat: Gitter = https://gitter.im/aio-libs/Lobby
+  Chat: Matrix = https://matrix.to/#/#aio-libs:matrix.org
+  Chat: Matrix Space = https://matrix.to/#/#aio-libs-space:matrix.org
   CI: GitHub Actions = https://github.com/aio-libs/aiohttp/actions?query=workflow%%3ACI
   Coverage: codecov = https://codecov.io/github/aio-libs/aiohttp
   Docs: Changelog = https://docs.aiohttp.org/en/stable/changes.html