update setup.py

Author: bieniu

setup.py

@@ -12,14 +12,11 @@
     url="https://github.com/bieniu/gios",
     license="Apache 2",
     packages=["gios"],
-    python_requires=">=3.6.0",
+    python_requires=">=3.6",
     install_requires=["aiohttp"],
     classifiers=[
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python",
-        "Programming Language :: Python :: 3.6",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
         "Operating System :: OS Independent",
     ],
     setup_requires=("pytest-runner"),