Really do not use asyncio's timeout lib before 3.11.2 (#2699)

4802530 made async-timeout required
only on Python 3.11.2 and earlier. However, according to PEP-508,
python_version marker is compared to first two numbers of Python version
tuple - so it will evaluate to True also on 3.11.3, and install a
package as a dependency.

setup.py

@@ -34,7 +34,7 @@
     install_requires=[
         'importlib-metadata >= 1.0; python_version < "3.8"',
         'typing-extensions; python_version<"3.8"',
-        'async-timeout>=4.0.2; python_version<="3.11.2"',
+        'async-timeout>=4.0.2; python_full_version<="3.11.2"',
     ],
     classifiers=[
         "Development Status :: 5 - Production/Stable",