feat: add classifiers for python3.9 and remove for python3.5 (#295)

Co-authored-by: Frank Natividad <frankyn@users.noreply.github.com>
Co-authored-by: Tres Seaver <tseaver@palladion.com>

setup.py

@@ -78,10 +78,10 @@
         "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],
@@ -90,7 +90,7 @@
     namespace_packages=namespaces,
     install_requires=dependencies,
     extras_require=extras,
-    python_requires=">=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*",
+    python_requires=">=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,!=3.4.*,!=3.5.*",
     include_package_data=True,
     zip_safe=False,
 )