add python 3.11 tests

uvloop is disabled on python 3.11 for now due to cython incompatibility.
a new cython version has since been released but uvloop needs to be built against this new cython version.
see MagicStack/uvloop#450 and MagicStack/uvloop#459

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
           - '3.8'
           - '3.9'
           - '3.10'
-          # - '3.11.0-alpha.4'
+          - '3.11.0-alpha.4'
         db:
           - [mysql, '5.7']
           - [mysql, '8.0']

tests/conftest.py

@@ -3,11 +3,21 @@
 import os
 import re
 import ssl
+import sys
 
 import aiomysql
 import pymysql
 import pytest
-import uvloop
+
+
+# version gate can be removed once uvloop supports python 3.11
+# https://github.com/MagicStack/uvloop/issues/450
+# https://github.com/MagicStack/uvloop/pull/459
+PY_311 = sys.version_info >= (3, 11)
+if PY_311:
+    uvloop = None
+else:
+    import uvloop
 
 
 @pytest.fixture