add python 3.11 tests (#722)

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

requirements-dev.txt

@@ -8,5 +8,5 @@ PyMySQL>=1.0.0,<=1.0.2
 sphinx>=1.8.1, <4.4.1
 sphinxcontrib-asyncio==0.3.0
 sqlalchemy>1.2.12,<=1.3.16
-uvloop==0.16.0
+uvloop==0.16.0; python_version < '3.11'
 pyroma==3.2

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