CI: Extend test matrix by Python 3.9 and 3.10

Author: amotl

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        python-version: [3.6, 3.7, 3.8, pypy3]
+        python-version: ['3.6', '3.7', '3.8', '3.9', '3.10', 'pypy3']
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python

setup.cfg

@@ -22,6 +22,8 @@ classifiers =
     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
     Topic :: Internet
     Topic :: Software Development
     Topic :: Software Development :: Libraries
@@ -38,7 +40,7 @@ setup_requires =
     setuptools_scm>=4.0
 
 install_requires =
-    requests>=2.23.0
+    requests>=2.23.0,<3
 
 [options.extras_require]
 test =