Update redis-py testing matrix

- Update tested versions to 5, 6, and main.
- Simplify matrix to focus outliers against known versions.

Author: carltongibson

README.rst

@@ -19,9 +19,11 @@ There are two available implementations:
 
 Both layers support a single-server and sharded configurations.
 
-`channels_redis` is tested against Python 3.9 to 3.13, `redis-py` versions 4.6,
-5.0, and the development branch, plus the current Channels version 4.x and the
-development branch there.
+`channels_redis` is tested against Python 3.9 to 3.13. We test with the latest
+`redis-py` version, as well as the older 5.x branch and main development branch,
+using the latest stable Python and Channels versions. We test the Channels
+development branch, using the latest stable Python and the latest `redis-py`
+release.
 
 Installation
 ------------

tox.ini

@@ -1,7 +1,8 @@
 [tox]
 envlist =
-    py{39,310,311,312,313}-ch{4,main}-redis50
-    py311-chmain-redis{45,46,50,main}
+    py{39,310,311,312,313}-ch4-redis6
+    py313-chmain-redis6
+    py313-ch4-redis{5,main}
     qa
 
 [testenv]
@@ -12,8 +13,8 @@ commands =
 deps =
     ch4: channels>=4.0,<5
     chmain: https://github.com/django/channels/archive/main.tar.gz
-    redis46: redis>=4.6,<4.7
-    redis50: redis>=5.0,<5.1
+    redis5: redis>=5.0,<6
+    redis6: redis>=6.0,<7
     redismain: https://github.com/redis/redis-py/archive/master.tar.gz
 
 [testenv:qa]