Update pytest and run CI with Python 3.10 (#9)

Author: slovdahl

.github/workflows/test.yml

@@ -16,7 +16,12 @@ jobs:
     runs-on: ubuntu-20.04
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version:
+          - '3.6'
+          - '3.7'
+          - '3.8'
+          - '3.9'
+          - '3.10'
     steps:
       - uses: actions/checkout@v2
       - uses: actions/setup-python@v2

requirements_frozen.txt

@@ -32,7 +32,7 @@ pytest-cov==2.11.1
 pytest-flake8==1.0.7
 pytest-pylint==0.18.0
 pytest-runner==5.3.0
-pytest==6.2.2
+pytest==7.0.1
 python-dateutil==2.8.1
 pytz==2021.1
 pytzdata==2020.1