Fix release upload errors

Author: kennburger

.travis.yml

@@ -50,6 +50,7 @@ deploy:
     python: '3.7'
     branch: master
 - provider: pypi
+  setuptools_version: "60.8.2"
   user: __token__
   password: $PYPI_TOKEN
   repository: https://upload.pypi.org/legacy

setup.py

@@ -61,10 +61,10 @@
       classifiers=[
           'Programming Language :: Python',
           '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',
+          'Programming Language :: Python :: 3.10',
           'Development Status :: 4 - Beta',
           'Intended Audience :: Developers',
           'License :: OSI Approved :: Apache Software License',