chore: bump version to 3.0.0a2

Author: kgriffs

setup.cfg

@@ -1,6 +1,6 @@
 [egg_info]
 # TODO replace
-tag_build = dev5
+tag_build = a3
 
 [aliases]
 test=pytest

setup.py

@@ -163,6 +163,7 @@ def load_description():
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
+        'Programming Language :: Python :: 3.9',
         'Programming Language :: Cython',
     ],
     keywords='wsgi web api framework rest http cloud',