imporvement: update setup.cfg

Author: leafcoder

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = django_covid19
-version = 0.4b1
+version = 0.4rc1
 description = A django app of covid-19 API in countries around the world, provinces and cities in China, and states in the USA.
 long_description = file: README.md
 long-description-content-type = text/markdown
@@ -14,18 +14,19 @@ classifiers =
     Development Status :: 5 - Production/Stable
     Environment :: Web Environment
     Framework :: Django
+    Framework :: Django :: 2.0
+    Framework :: Django :: 2.1
     Framework :: Django :: 2.2
-    Framework :: Django :: 3.0
     Intended Audience :: Developers
     License :: OSI Approved :: MIT License
     Natural Language :: Chinese (Simplified)
     Operating System :: OS Independent
     Programming Language :: Python
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3 :: Only
+    Programming Language :: Python :: 3.5
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
-    Programming Language :: Python :: 3.8
     Topic :: Internet :: WWW/HTTP
     Topic :: Internet :: WWW/HTTP :: Dynamic Content
     Topic :: Software Development :: Libraries