setup: Update package metadata

setup.cfg

@@ -8,7 +8,7 @@ long_description_content_type=text/markdown
 description=Idiomatic asyncio utilities
 license=MIT
 classifiers =
-    Development Status :: 4 - Beta
+    Development Status :: 5 - Production/Stable
     License :: OSI Approved :: MIT License
     Intended Audience :: Developers
     Framework :: AsyncIO
@@ -17,14 +17,13 @@ classifiers =
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
     Topic :: Software Development
 url = https://github.com/achimnol/aiotools
 project_urls =
     Documentation = https://aiotools.readthedocs.io
     Tracker = https://github.com/achimnol/aiotools/issues
     Source = https://github.com/achimnol/aiotools
-    CI: AppVeyor = https://ci.appveyor.com/project/achimnol/aiotools
-    CI: Travis = https://travis-ci.com/achimnol/aiotools
     Code Coverage = https://codecov.io/github/achimnol/aiotools
 platforms =
     any