Update dockers tags (#2409)

tox.ini

@@ -18,7 +18,7 @@ envlist = {standalone,cluster}-{plain,hiredis,ocsp}-{uvloop,asyncio}-{py37,py38,
 
 [docker:master]
 name = master
-image = redisfab/redis-py:6.2.6-buster
+image = redisfab/redis-py:6.2.6
 ports =
     6379:6379/tcp
 healtcheck_cmd = python -c "import socket;print(True) if 0 == socket.socket(socket.AF_INET, socket.SOCK_STREAM).connect_ex(('127.0.0.1',6379)) else False"
@@ -27,7 +27,7 @@ volumes =
 
 [docker:replica]
 name = replica
-image = redisfab/redis-py:6.2.6-buster
+image = redisfab/redis-py:6.2.6
 links =
     master:master
 ports =
@@ -38,7 +38,7 @@ volumes =
 
 [docker:unstable]
 name = unstable
-image = redisfab/redis-py:unstable-bionic
+image = redisfab/redis-py:unstable
 ports =
     6378:6378/tcp
 healtcheck_cmd = python -c "import socket;print(True) if 0 == socket.socket(socket.AF_INET, socket.SOCK_STREAM).connect_ex(('127.0.0.1',6378)) else False"
@@ -47,7 +47,7 @@ volumes =
 
 [docker:unstable_cluster]
 name = unstable_cluster
-image = redisfab/redis-py-cluster:unstable-bionic
+image = redisfab/redis-py-cluster:unstable
 ports =
     6372:6372/tcp
     6373:6373/tcp
@@ -61,7 +61,7 @@ volumes =
 
 [docker:sentinel_1]
 name = sentinel_1
-image = redisfab/redis-py-sentinel:6.2.6-buster
+image = redisfab/redis-py-sentinel:6.2.6
 links =
     master:master
 ports =
@@ -72,7 +72,7 @@ volumes =
 
 [docker:sentinel_2]
 name = sentinel_2
-image = redisfab/redis-py-sentinel:6.2.6-buster
+image = redisfab/redis-py-sentinel:6.2.6
 links =
     master:master
 ports =
@@ -83,7 +83,7 @@ volumes =
 
 [docker:sentinel_3]
 name = sentinel_3
-image = redisfab/redis-py-sentinel:6.2.6-buster
+image = redisfab/redis-py-sentinel:6.2.6
 links =
     master:master
 ports =
@@ -101,7 +101,7 @@ healtcheck_cmd = python -c "import socket;print(True) if 0 == socket.socket(sock
 
 [docker:redis_cluster]
 name = redis_cluster
-image = redisfab/redis-py-cluster:6.2.6-buster
+image = redisfab/redis-py-cluster:6.2.6
 ports =
     16379:16379/tcp
     16380:16380/tcp